Fook me, what a ball ache!
Turns out it was a fueling issue. Idles spot on now and drives fine but has lost it's urgency at top end as I haven't put the strobe or the gas tester on it yet.
Will try and get that done in the next couple of days, at some point when I'm flush I'd like to take it to a pro, especially when the clearances are sorted. At least I can relax a little now with the knowledge that it's got a new belt on.
little bit of evidence, old belt didn't look too bad.
Really must look into the oil leak, it doesn't look good.
Thanks tech for the reply... the old belt was wrong hence why I had to start from scratch.