it only leaks when its being driven, doesn’t seem to leak when just on tickover.

Ive had it all apart today and removed the crank seal and ive think ive found the problem.
I have a CNC aux pulley bolt and ive noticed before oil pooling on the aux pulley but just put it down to it dripping off the cam belt. Now as i loosened the aux bolt oil started to drip out from around the bolt before it was even all the way out and it seems the tread on the none standard bolt isn’t quite large enough as the bolt rattles around when not 100% wound right in so I think the oil has been pushed out the tread when the pressure is up.

Does this sound plausible or am I talking shite?