I wish you the best of luck with that Stuart.
See below as to what the USA can get hold of.
http://www.jimellisvolvoparts.com/sh...rimLevel=20459
In my opinion, Item 5 is what you need, but for only the smaller of the 4 "o" rings. The other rings appear to be for the pump and filter, as are 4 screws +2 for the DEM. The metal plate which has the rubber seal all round the edge I do not think forms an oil tight seal around either the pressure valve or solenoid, and I suspect its merely a support for those components, but has a rubber seal so that there is not metal to metal contact. If the DEM is leaking oil from the external Black silicon/bitumen compound, I'd be telling Lucas and asking that he reseal the unit. If it had not been leaking oil, you would never have known that rain etc could get inside and reak havoc with the electronics.. until it failed.
IIRC his repairs are guaranteed 2yrs..
If you can measure the old "o" rings accurately you might be able to buy off of Web/ironmonger. I got a 42mmDia charge pipe "o" ring locally for 20p against Volvo approx. £5.00
Cheers
Bob
Cheers
Bob