[WTD] Pentax M series Film Camera (Not Working)

Hi all,

I have a Pentax MX film camera that I am trying to repair. It is mostly working.
I have established that I can buy a used example for far less than is will cost me to get this commercially repaired, so that route is out.
I am looking for a non working Pentax M series body that is not working to practise on. They are all largely similar enough in construction. Cosmetics is unimportant.
I have to take the mirror box out, so I don't want to try on a camera that could be viable.
Has anyone got something that they are willing to part with for for cheap or postage money?
Something like an ME, ME super, Super A, or Super Program or ideally an MX?
I understand they come up on ebay frequently, but such is the market for working cameras that even spares ones have buy it now or starting prices that means the vast majority don't sell or, I suspect are bought by repairers if the condition is tidy enough.

This may be a long shot, but here goes.
Thanks for looking.

Graham.