I hope this does'nt come back and bite you on the bum Richard - i'd be worried about those low compressions.
The ECU surely does shut down the injectors when it detects a misfire, and that includes low compressions even slightly down in comparison to others.
I'd even be worried about just replacing valves having taken the head off. Its well known these suffer from piston ring problems and oil usage.
Best of luck!

Colin