Compressor is faulty on my RRS - so looking at replacing and came across this listing:
http://www.ebay.co.uk/itm/RANGE-ROVER-L322...0761264469

Looks like it comes with instructions for replacing seals etc rather than the £500 replacement compressor

Anyone gone down this route and just replaced seals? RRS HSE TDV6 Autobiography

When I had my L322 I fitted the service kit, just piston ring and o ring. Definitely made a difference and really cheap and did fix the problem but I did feel I should have bought a new compressor, especially if you're planning on keeping the sport.

If you do go down this road then make sure you fit the piston ring the right way up. I didn't think there was any difference but there is, the wrong way did not produce enough air pressure to do hardly any movement, had to strip and refit and then all was good. 2006 Supercharged

Thanks for that. Gives me some confidence. Just ordered it as I dont mind getting my hands dirty.
Plus £20 is a bit better than £500! RRS HSE TDV6 Autobiography

I spent a sunday during the summer trying to do this. I did eventually get the compressor off but spent an age trying to remove one of the compressor pipes. Then when I did get it off, I recall there was a bolt/ screw that needed to be removed. I had to use the vice in the garage to be able to get enough force to remove it and it sheared and so as far as i could see, the part was then unrepairable. I got the replacement AMK compressor with new relay and software fitted at RR London ( ) for £495. Here the post: http://www.rrsport.co.uk/forum/topic32424.html

I have had my compressor repaired today. Don't just think the seals will fix it though, we took my compressor off today and turns out the guy at landyair is based just round the corner fom me. I rang him to to order a kit and he said while I'm local to bring the compressor round and he would test it for me. Glad I did, turns out there was nothing wrong with the rings but there was a crack in the back plate of the compressor and air was leaking out. He made me a new back plate and replaced the crystals in the air dryer. We then re fitted it, cleared the fault codes. £70 and its running sweet as now. Great service.

One thing to note, the pipes are only connected by a push fitting but mine were a pig to get out as there was a build up of crud, mud and salt......... Use plenty of lube