Apologies if this is in the wrong section

My bike went in for its MOT on thursday. I had no concerns about it at all and was shocked when the tester came out and told me had failed. It failed because of the rear tyre being fitted the wrong way round. The tyres were fit about a month ago and I am going back with the MOT failure certificate and the bill to correct there mistake for them to refund.
I was wondering if there were any legalities involved with this sort of thing? The more ammunition i can take in with me the better.

You'll be glad to hear though that the bike has its MOT now though and apart from the tyre the only caution was a noisy exhaust I will not be using the garage again either. FYI it was Downton tyre and autocare.