Hey Mark,
I can only say what I witnessed
Mag check was ok (RPM drop on each of the mags). And yes, it was quite shaky, but it definitley went up to 1700RPM. It turned out that one cylinder had almost no compression and another was quite low on it.
However, I'm still on the status I got from a first quick check from our mechanic and haven't had any updates.
I'll keep you guys posted on the final diagnostic.
Cheers,
Alex