blackstorm wrote:Defo sounds like you'd be cheaper bunging in a new engine and keeping yours for spares
It will cost the same if not more to buy a secondhand replacement and have it fitted.
Also, you have the issue that the engine thats being bought might be dodgy too. You then have to spend several hours (5-10) swapping ancillaries across..all at £40+ an hour for labour. Then fitting is going to cost too. As I have found, as soon as you start to remove engines you start to find other things that need reparing!
Replacing valves etc is not a big job..all be it there are 24 of them to check

...my V8 takes about 5 hours to replace the cam shaft, push rods and valves.
Don't forget, it might be worn piston rings...is it blowing smoke, worn liners, cracked block or head or leaking cylinder head gasket, ?? If its losing compression down one side as you said I would lean more towards the gasket or cracked head/block.
Also, did you do the compression test on a hot or cold engine? Cold engines will give a low reading.
There is a chap not far from you who races Galants (or it might be his brother in law...they both race anyway)..he lives in Sauchen in one of the big houses that faces the A 944. You will see the cars sitting in the garden..friendly chap..knock on his door and see what he says.