Dealer reneged on warranty

Hi I bought second hand Mini 3 months ago, dealer gave me 6 month warranty, albeit this was written at bottom of invoice without any actual breakdown of what the warranty covered. Had to get new battery and since found that strut is bent! This would cost nearly a grand to repair. Dealer now at new premises claiming he is no longer a director and refuses to deal with problem.
What can I do?

Thanks

Complicated, he was joint director with somebody who has many companies, Ltd and otherwise. Now claims just to be employee for somebody totally different, the whole thing a racket I reckon.

Definitely not sole proprietor. He was a director of a company for a few months until his appt was terminated, sacked apparently, and now claims to be `just working` in a completely different garage. The other director has multiple companies and it seems to me has fingers in a lot of pies.