Some of this is down to Heather herself. She was among the first of the professional women racing drivers, and that meant she had to be many times better than all the chaps before she even got a look in. The start of her career came in kit cars, with an O & C Sprint. This got her totally involved, and she just kept bashing away at the prejudice as well as the lap times until she began to get some results that nobody could argue with.

These included success with Formula First, the Willhire series with a Cosworth Sierra, some F3 racing in Japan, and a spell driving trucks. Quick trucks, we're talking about. The quickest truck, in fact: Heather was the British champion truck racer in 1991. Even now, she can dispose of sausage, egg, bacon, beans and chips, a mug of tea and a slice in 11.26 seconds flat.

The Cadwell Park win was the first clear win for a Gardner Douglas replica Cobra, although Heather took one to a first in class win last year. It's not all down to Heather's skill, though: GD's Andy Burrows got a third place himself at Snetterton last year when he was still more or less running the engine in, and although no slouch as a driver, he's no Stirling Moss. So a good proportion of the win is down to the car.

When I first reviewed the Gardner Douglas car a while back, I said that it wasn't really anything much to do with Cobras at all. The chassis is a very sophisticated tubular backbone affair, which has more in common with the ideas of Lotus and TVR than with the twin drainpipe ladder chassis of AC's cars. Even back then, there was some clever stuff going on, with a most un‑Cobra like approach to the problem of balancing comfort and handling. Most Cobra replicators don't really spend much time and effort on innovation in this area, as they're mostly concerned with stonking performance and good looks. However, the engineers' approach that GD have always used resulted in a chassis that was developed for pure handling, and a body that was developed as a separate but rigid unit, attached to the chassis by many rubber mountings, allowing small movements in all directions and damping vibration and harshness to a high degree.

The GD Euro spec chassis is a newish idea: as well as using the traditional Jag rolling gear, you can now use Cosworth diffs, shafts, brakes and so on, with GD tubular wishbones and alloy uprights. This makes the whole car lighter, and allows fine tuning of the suspension: it also allows you to buy the whole set of componentry brand new, and to register the car as new with an "N" registration for 1995/6.

If you're feeling a bit naughty, you can take the Chevy small block up to 500 BHP and still use it on the road: if you go for ally heads and so on, the weight of the 5.7 litre engine isn't too bad either. American engines, particularly Chevies, are so cheap to rebuild compared to European engines: it's always an eye-opener when you actually start ordering bits, and the smaller bits can sometimes be flown over from the States faster than Ford dealerships can source bits of Sierra.

Talking about 500 BHP engines, that's what there is under the bonnet of the racer. This is the same car about which I waxed lyrical a few years ago in the earlier edition of this very publication, giving it some welly on the old word processor about pink and ice blue skies reflecting off gleaming bonnets. I should coco. The car looks just as good today, but its attitude to life has changed somewhat. It was light, friendly and slick before, and now it's a bit of a bitch, quite frankly.

It's only used for racing now, and has been rebuilt entirely to that end. The engine is a Chevy small‑block, but it's one of the heavy duty blocks with cross‑bolted main bearings. There is a fully balanced and sorted steel crank, the compression ratio is 11.5:1, the big valve full race head sports roller rockers, and the rev limit is 8000, although only 7500 of those are used on a regular basis.

The car is more or less to standard GD Euro spec, but it retains a Jag diff, which is more or less indestructible. The Scorpio rear end is quite tough too, but the car has stuck with the Jag diff although the rest of the suspension is Euro spec. The rear brakes remain standard, but the discs are grooved: the front brakes use Alcon four‑pot calipers and 12" discs. Mind you, it shouldn't be forgotten that every dead Jag comes with a free set of four‑pot calipers and big vented discs, and the Jag stuff all still pops on to the GD Jag chassis quicker than you can watch the build video. Yes, they do have a build video: and while Andy Burrows is no Quentin Tarantino, it's a useful idea and in many ways better than a manual.

There's no wimpy nonsense about windscreens and opening doors in the racing GD, although the dark blue colour and the smooth GRP means it still looks quite tasty. The body style was designed originally to use the full width Jag rear end, but with relatively narrow wheels and tyres: the idea was to produce something between the original fairly restrained 289 Cobra shape and the monster 427 shape with muscles bulging everywhere. The end result is fairly lithe looking, even when it's fitted with racing split rim wheels and fat tyres.

Where you would expect sidepipes or a pair of fat straight‑through exhaust pipes, there is a pair of big silencers crammed under the back of the car: the noise regulations are increasingly tough, and to get a car through scrutineering for noise is getting harder. This is a shame, as part of the excitement of racing is listening to a dozen engines screaming and howling round the track. Pretty soon there will be regulations about the smells of hot oil and burnt rubber: next there will be a 30MPH speed limit on all racetracks and we might as well all stay at home.

Still, the silencers for the moment only have to keep the noise down at a specific engine speed, and there are lots of other engine speeds at which the engine still sounds glorious. One of these speeds is where Heather revs it right up as she see the red light on the grid, and as the green flashes on and she dumps the clutch, the deep roar of the Chevy can still be heard above the howling of Jag sixes and the raspy farting of four cylinder cars.

As the smoke clears, Heather can be seen hurtling away from the rest of the pack, pushing her luck to the limit in the first half mile to create some clear space between herself and the others. If she can open up a decent gap, there is a good chance that the rest of the drivers will be too busy fighting amongst themselves for second place to worry about catching her up. As there are two C‑Type replicas doing just that, she is proved right. Ten times she thunders round the upsy downsy and very twisty Cadwell Park circuit: no fuss, no drama, no histrionics, just very smooth and very quick indeed.

Time after time she boots it along the top straight and hauls the car down from a frightening speed to just slow enough to get round the twisty bits and the hairpin, and as the sound of her exhaust fades into the distance, the tangle of Jags and assorted others jam more or less into a line to take the same corner a few moments later in a chorus of screeching tyres and drifts of blue smoke.

Before too long, the final lap comes up and Heather streaks past the chequered flag, to a surprisingly loud chorus of cheers from the crowd. This series is good racing, as the cars are frequently quite close replicas, the Jags in particular. The Gardner Douglas certainly doesn't behave like a racing Cobra, more like a Lotus Elan (I don't mean the blobby thing, I mean the proper one). The C‑Type Jags look and sound like the real thing, which is probably why the Retro Sports GT series is looking increasingly promising.

It used to be known as the Historic Replica series, but for some reason it was changed: I'm not sure why, as Historic Replica Racing is a pretty accurate description of what you do when you race historic replicas. It's good racing, and I can recommend going along to watch. Particularly next year, because if enough discerning individuals buy my own Jag XK replica kit, I will be racing one myself. However, I don't expect to see Heather in my mirror. Not until she laps me, anyway.

Did I have a crack at driving the GD racer? Yes, I did, for a brief spin round the paddock before it went back on its trailer. Just to get a feel for it. You scramble aboard over the door, then snug down into the seat. The roll cage is effective rather than pretty: a single roll over bar doesn't in reality offer much more protection than a bandanna, but if you find yourself weaseling in amongst a tangle of bars that looks like a children's climbing frame, that will probably do you some good.

No ignition switch as such, just a removable red plastic cut‑off key that isolates the whole electrical system in the event of a woopsy. Turn that on, turn on the pumps, poke the starter. The engine is surprisingly co‑operative, and just starts with no fuss and idles reasonably smoothly. The gearbox is the industrial strength top‑loader four‑speed, and even with a Hurst shift it's a bit of a pig, with a very small gate and a firm tug needed to get the message through. Even so, the clutch is the only real reason why this car can't be used on the road.

It's the most evil clutch I can remember: not too heavy, just on or off. It's a small, very butch multi‑plate racing‑only item, and you simply can't let it in smoothly. When it wants to, it suddenly grabs, and you either stall or boot it and go. The easiest way to get going is to give the engine some revs, and then just let it go and catch the resulting drift as the wheels spin and the back steps out. Of course, the only reason for the existence of this clutch is to get Heather going as quickly as possible, and this the clutch does with clearly demonstrated effectiveness.

If you want your views on women drivers changed, go see a Retro Sports GT race with Heather and a GD427 in it. Mind you, I didn't watch her parking it...