Hi, I don’t have any contacts for you but if I can give some encouragement. I started a full engine rebuild (engine was fully seized) with zero mechanical knowledge and no workspace. I year on I have fully rebuilt the bottom and top end and the engine is now fully working.
I also used a donor engine for various parts and where needed I bought online from David Silver Spares or CSMNL.
I have some parts left over and I’m based in the East Midlands. If you do decide to self build then there are lots of people on here that have been helpful to me.
That said, would someone like Mint Customs or Pier City do an engine rebuild? I think they are both South England based.