The car wasn't misfiring. When idling from cold the revs would bounce slightly. He asked what this was. I was told by my mechanic who changed the valvetronic motor, it needs to bed in and needs a good run and for the engine to learn. This was work which I had carried out in May and I had no reason to question this. Since then it had done 40 miles, so I didn't think this was enough to bed in. There was no smoke or loss in coolant. And the car was test driven hard by the buyer for 20mins, 10 mins by me and left idling for 20-30 minutes over 2 separate days. At no point was there any concern and the only feedback he gave was, the car is mechanically sound, however he is concerned about the bodywork, which he then made an offer of £15,000. I refused, but said I would sleep on it. The following day I asked for £16,500 and we met and agreed at £16,000.