i'd stick to OEM too, I've used armstrong(really, really cheap) and while they work fine when new, don't expect longevity, BOGE don't just supply Land Rover, they're OEM on Jaguar too and they last for ages along with performing superbly.
Irishrover, are you in a mood today? A request for what has been found to be best VFM is not how can I run this on nowt. We come here to find out stuff we don't know, if you can afford to waste money buying without proper information, you go ahead, but get off the sane and sensible world's case. Incidently I bought my P38 in the full and certain knowledge that it drinks petrol, is heavy on brakes, has electrical issues beyond compare and air suspension that frequently doesn't, and to date I'm amazed as to how little I've had to put into it in terms of money(tyres) and time (sod all). Rant over