ill try my best lol, it would be a good sideline though wouldnt it, "hey do you know anyone who's got kittens for sale?" "yea hold on a sec ill jus go squeeze a couple out for you" lol
NG it shouldtn matter if you cant find a receipt/invoice etc, as long as you paid by card you can just use your statement as proof of purchase, if you paid by credit card its even beta cos youre covered by the consumer credit act, anything you spend can be claimed back if the garage doesnt play ball, i think you hold the credit card company "in breach of contract" or something like that, dont really know if its the same for a debit card though.
But id still give trading standards a call if i were you, theyll tell you exactly what your rights are, and even if you dont go after the garage trading standards will anyway, which is always nice!