Thanks for the comrade, I hope that is the case. The good thing is at least now he's seeming to accept that he's sold it me as a dealer as opposed to private, because I know if the latter you're basically screwed.
I did ask for a refund initially, to which he disagreed, he has said initially he would pay for repairs, but throughout has repeated the car was fine when he sold it and if it's damaged I've done it myself - given I contacted him the very next day with an initial concern, I think that's almost laughable. I've since said I'll go 50/50 on any repair costs as a means to get the problem sorted so hope he'll go for that. Wouldn't like to go down the legal route, but will have to if he leaves me with no alternative.