My motor is reaching 180k & still fires up on the first turn

But I think in the near future it could do with a rebuild (Re-bore & Valve guides). Problem is I having troubble finding anyone in the Southport - Liverpool that can rebuild my motor

What is a good price for a full rebuild or replacement motor??
I don't really want to sell her, but if I cannot get the engine sorted then......
Oh it's a 8v K-ket engine.
Help Guys, Jay