So the past two days it has been noticeably more reluctant to start (
I took a video yesterday and no, it didn't need any throttle to eventually start) but running OK when warmed up.
Then today driving it felt like it was bogged down and running rich all the time.
I'm thinking it might be best to focus on the starting? And that might be a quick way to an answer.
Have ruled out:
Compression
Plugs/coils/leads
Cam sensor (was swapped for a new one and then back to original)
There can't be many more things 'required' for it to start? The crankshaft sensor springs to mind but that's about it.