I've had a look on the net and it seems the 6 months thing applies, its down to him to prove the fault wasn't there when I bought the car, how he'd manage to do that though, I haven't got a clue. From reading through the links posted above, I can't see how he could prove the fault wasn't there, there is only small bit of history which amounts to the last 5 MOT's and receipts for work carried out over the last 4 years at MOT time, service etc. The car was MOT'd 2 months before I bought it, which it failed, and was subsequently repaired and retested.
And no the car isn't driveable, they have the car, its now in a workshop somewhere having the gearbox stripped to see what damage has been done. So far I know it has stripped the splines from the driveshaft, gearbox end, and the stripdown is to see what other damage may have been caused. He's expecting me to foot the bill, albeit at trade rates, but I don't think that'll be happening now.
It also seems there may be a case of misdescription as well, the car was advertised as having aircon, which doesn't work, and he'll only repair if I pay for the pipe to repair. Seems it should have working aircon as it was advertised as such...