Thinking of reinstalling my self levelling what with the weight of an 80 litre tank and the Mr's arse in the back.

replaced the 20 amp fuse and the relay in the interior fuse box but not a fart from the compressor, I know it's there as I changed the front wing a while back and it was working when the leaking self levellers were removed by the skin flint of a previous owner with normal ones,is there anything else that could have been removed to stop it working?

If it's not been used for a long while it's probably siezed up/corroded. The pump shifts air which contains water vapour, thsua the bores would be wet/damp and an easy target for corrosion if left unmoved for a long time IMHO ..