Some good responses above.
Speaking from both sides of the fence.
I sold an UNO years ago to a lad who constantly phoned me up with the slightest of issues,turned out he'd driven it pissed with 10 of his mates in it round the rugby club field until it effectively rolled into a ditch in the field,fucked the lower arm up and then tried saying I'd got a dodgy ticket on it.
His dad was the big man down the phone threatening court etc so basically told him to get fucked and if he thought there were issues,take it back to the mot centre as I'd paid full whack for a ticket and had the failures done.
He did and his "I'll take you to court patter worked" and he had £200's worth of work done for free.
I should point out the driving round a field incident only came to light after he's had it sorted from a mate if his who slipped up.
Conversely.
Bought a ka for good money off a mate for my sister with 12months ticket on it,I knew it was bumped but the repair was good or so it seemed.
She drove it about with no issues for a year then took it locally for a mot,it failed on having a crumpled chassis leg.
I told her bring it home and we'll get my mate to look.
He saw it but said it was minor so passed it.
Same again 12 months later,but this time the other boy working there failed it,which I wasn't happy with.
I did a bit of tinkering with it and took it to another mot centre who passed it,advising on the leg.
Passed the next mot ok then failed for other things so got broke up.
I went back to the guy who i bought it off who said it could have been my sis that caused it and it had passed an mot etc etc.
Tough one,I didn't see him as being totally wrong about that but had she not known me and just been a simple punter it could have got messy with court etc.
If I were you I'd ask for a refund or ask to get the work done and the car re mot'ed.
If he gets shitty phone the lot centre and explain the situation,explain you've spoken to him first but he's blaming them etc.
It's 50/50 what they'll do about it but my guess is they'll repair it for free or even just parts cost which is fair IMO.
You then know the car is right,happy days.