Update:
Managed to get a J type fuse just now (Big up Halfords open Boxing Day

) and fitted fuse - and everything started happening. I asked it to raise and screen said something about raising - I could hear the compressor when outside the car, quite faint mind - I expected it to be a reasonable loud brrrrrrddd. That said, maybe thats because when I looked at the dash it said vehicle raising slowly (or similar). It looks like its raised fair bit from its height before i started, I stupidly didnt measure where it started from before my experiment. I couldn't hear any hissing air leaks and assume compressor can make a fair amount so a leak would be evident if it were stopping it going up by a significant amount. I turned engine off after perhaps 2 minutes so I didn't blow fuse again pending some replies here if poss. All suspension warnings and orange light went off. I had selected off road height it said on screen.
So, does it sound like weak compressor? Are they reconditionable - I've seen kits but most searches only talk of replacement so are they a lost cause or special tools req?