Sorry to go offtopic, but just fitted harnesses to mine.
Its a 80/81 car and never came with rear belts.
The front harnesses are bolted to the rear seat.
I have the rear seat in, but it is not accessible.
Am I breaking the law?
Jack, you're fine. Your car didn't have to have rear seat belts as OE anyway.
As for removing the rear seats, yep, that's a get out. If you have no rear seats, then why should you need rear seat belts right? I am not sure if this means that the DVLA have to be informed and you 'should' get the log book changed to 2 seats, rather than 4??? I guess technically you could do, but I'm not sure on the rules there.