I got it sorted now. Somehow leads 2 and 4 were the wrong way and the plugs are shot. Put normal 1.8 plugs in and it runs spot on- not tried driving it. Put the RS ones back in and it died so must be plugs. Lead 4 was sparking over the block when I was checking them with pliars so I'd say that's shot too. Thing is though they were bought new 3 month ago.....
Plugs are all black and sooty so car Defo overfuelling. Where should I be looking first? Temp sensor? Lambda?