Cool. That's the best thing it could be.

It's tough diagnosing a problem without having the engine in front of you, and since you'd replaced the plugs it was the last thing you'd expect, so that's why we were all thinking it was a stuck valve.

Anyway, that's a good reminder to everyone to have a good spare plug in the toolbox as a test plug (along with a long lead that can fit any spot on the motor).

Good job mate, and I'm happy we were wrong. (I was secretly hoping it wasn't a lobe worn off your cam!)