Roger, grateful for enlightenment in respect of scavange/oil pumps, thought both in one housing. Scavange has no evidence of leaks and at idle at least seems to be pumping plenty of oil back into tank so on balance probably not going to meddle with it, belt on parts list though. And if oil pressure ok then presumably don't need to worry about pressure pump either. So thanks again Roger, earlier posts had me ear marking chunk of budget but can now divert back to nice to haves.
Thanks to others for input and noted titan/ burton in case of future need.