if it was a camshaft sensor woudnt the fault be there all the time?
plus as jim says it should show on live data.

yep changed all the coils and it cures the fault for all of 1/2 a road and its back.
plugs are recent and clean and dont show any faults, and again if it was under load and failed it could be plugs, but surely not while just idleing, as its not overfuelling and fouling them like a cossie does.
vanos seems to be working fine.
when it runs ok it has full power, and the vanos is silent.