Sounds like you may not have done enough homework before fronting up for inspection.

Copper has been a NO-NO for decades & bolting through body sheet metal without suitable reinforcing is not really a good idea.

Seat belts. These things must be thirty years old by now. It's likely that they wouldnt pass the original compliance test now anyway.

You must have known about the wipers for a while, so that it is really just poor housekeeping.
It would seem that your "mod plater" is just doing what he is paid to do, covering his arse.

Never mind, these are all just relatively minor things, & he hasn't picked up on anything serious, so congratulations, you will soon be back in action.