Coil pack.....
that.
Start with the simple stuff first.
What makes you think it has more serious problems?
Absolutely nothing whatsoever - I just like to follow a methodical diagnostic process, and not replace parts based on guessing what could be wrong (as Mr DTM ingrained in me many years ago!)
As it happens though, I think you're right about the coil pack.
I eliminated compression - good compression on all cylinders.
Removed the spark plugs, they are all in good condition.
Swapped the plugs between cyls 1 and 4, and the problem did not move - meaning it's not a spark plug issue either.
Can only leave the coil pack, really - which dropped on the doormat this afternoon, and I'll pop it on tomorrow
Car has only done around 35k, the engine looks literally brand new