4.6 Oil pump parts

I'm rebuilding a 4.6 to drop into my 3.9 300 shape disco, I'm using the GEMS timing cover as I'll be using a programmable ECU and so the p38 oil pump cover etc. I've fitted new oil pump gears and I pulled the pressure relief valves to check the spring length. I am now having trouble getting hold of the little o ring seals that fit on the caps that hold the pressure relief springs in. Landrover will only sell a whole pump assembly. Has anybody got any ideas where I might get some? Ideally I'd like to put new springs in but as the existing one are still long enough I feel that might be overkil.

Has anyone had issues with the oil filter fouling the front diff? I notice the filter is vertical on the p38 housing rather than canted ala D2. I was planning to get a plate and some hose from mocal and relocate the filter if it does foul....