I always cringe when I see this in adverts:
"SINCE I'VE OWNED THE CAR ITS ONLY EVER BEEN RAN ON SHELL V POWER, GARAGED EVERY NIGHT, DRIVEN GENTLY WHEN ENGINE COLD AND ALLOWED TO TICK OVER FOR AT LEAST 30 SECONDS BEFORE ENGINE SWITCHED OFF"
Just seems like your trying to hide something regardless of whether you are or not.
Ive just sold two cars so I'll share my experience's.
I put a TDI Passat Estate on Ebay, the exposure and amount of people that viewed (nearly 1500 hits!) or had the car on 'watching' was amazing, I also just sold my Golf GTI which I put in Autotrader, didnt hear anything for the first 3 weeks, had it advertised for £17k which was really good value imo, after three weeks some guy rang me up and haggled me down to £16800, he then paid me £50 and the train fare home to deliver it to Bristol. Of course the advert in Autotrader ran for the full six weeks (couldnt be bothered cancelling it) and I had loads of calls in the last two weeks, sort of wish I'd waited now but hindsights a great thing.
Pistonheads didnt get me anywhere but then again its free so cant complain.
Ebay cost me about £20 (might be a bit higher for yourself due to different values) and Autotrader was £35 for 6 weeks on their website.
If I was in your position I would try Ebay first, if it doesnt get high enough then Im sure you can end the auction or *coughfixitsomewaycough*.
Nice car btw, Im after a CTR as well, preferably a white import which seem to be quite rareish...