I checked for spark on all four plugs and all seemed ok. Cleaned them up some more and it started with foot held to the floor. Took it for a run and it's good as gold. Starts and stops perfectly.

It does 'beep' when you start it, but it's done that for ages?

Think I'll replace the plugs to be on the safe side, and if it does it again the coil pack too.

Thanks for your help guys, it's what PF does best!