hi Alan apologies should have measured those events
this caught my eye because i recently had one with similar symptoms at ours
low cranking compression and runs fine otherwise i was looking for an expo? it came in for non start i got very similar readings to yours i had low compression on one cylinder and two weak coils replaced the coils and runs fine no obvious power loss to owner?
i thought Dr Jake was going right way maybe worn tappets as you say maybe springs?
thanks again look forward to what you find!