Sorry Idnan, just re-read your last post properly. Understand the valves can't be purchased separately from BMW. Michael has kindly emailed me a detailed plan of the PVC system so I'll have a look and get aquatinted with it.
I don't think I'll need the RB version as I'm only pushing 14psi and don't plan to go beyond that.
If I was to just order a full new crankcase cover from woods will this contain the whole pcv system including all valves or is there a part if the pcv system not connected to the cc cover that also needs to replaced?