Thanks MarkR - I will look at the belt tonight.
Dab - thanks for your response - have already changed plugs, HT, battery & also upgraded to the Walbro pump.

Would the oxygen sensors have any effect on starting? I do have some new ones I could try

Currently
2011 M3W
986 3.2S
Z4 M40i
Cectek Estoc
Midget 1275
1959 Frogeye Sprite
2022 Defender 90 HT