the car has 100k so if its not been replaced i suppose it could be tired.

when i sit in the car and look at 4 wheel drive screen it lifts and settles ok to off road and access height etc. so im wondering if it could be something else related to pump but not the pump itself?

im not against spending the money to hve it done but I dont want to do something for the sake of it.
Is there a way that I could see if the compressor that i have is the original?

Oh: just had call back from Landy main dealers and quoted £516-00 supply only for the pump plus VAT
So not sure how it can be doen for £5000-00 all in?

The pumps have gone in price latey. Mr dan @ duckworths is the man to talk to. If it has nt been replaced then at 100.000 it's done very well. You can keep using it as it is as it seems to work still and just live with the light coming on now and then but one day it will fail with the red light coming on. I payed £450 from duckworths with an indi charging 2 hrs to fit.

im prepared to replace it, i just dont want to replace it and then find its something else that causing the problem.

I dont know if it points to anything but tonight i drove it with the 4 wheel drive screen on, so i could keep an eye on it.
The suspension warning came on and at the same time, one of the wheels on the screen went down in height, i.e. there were 3 level with just one looking lower on the image, like it had dropped down.

Does that indicate a pump issue or could that be a problem with that corner of the car only, FWIW its the nearside front?

If one side is failing , you might need to look at the condition of the rubber boot on the air spring on that side, might be leaking, which means compressor has to work hard to keep up with leak - and this will accelerate wear on system. Soapy water sprayed on rubber boot might be needed to spot leak - and try this at full height, normal height (maybe hard to see at access height).
100K on the air springs you might also expect to have to start replacing.

If not the spring, could be the valve control block (but I think that would effect two sides if leaking ?), or the dryer/outlet valve on the compressor itself.

My '06 occasionally settles down on one spring (3 others are OK) overnight - so sticking valve somewhere leaking ? I was going to replace rear valve block and do compressor overhaul (new dryer, spring, seals) as cheap DIY fix (versus replacing compressor itself for $1000+) - which may not fix your issue if you have leaking spring or valve ....

(I'm not an expert on this stuff, but this is my best guess from reading about these systems - perhaps someone more qualified can chime in)

Further development:
Compressor replaced and worked fine with no warning for 3 days.
yesterday i got the little orange light come on saying suspension fault, this went off within a second.
i went to dealers yesterday and they plugged in to the diagnostic thingy and message came up faulty height sensor. He said it could be just a glitch and tbh the car seems fine, so he has reset the pooter on the car and said see what happens and if it goes again, to just have the sensor replaced.

My fear was that the compressor was not the initial problem but he gave me back the old one and it was an early model so could have covered a few miles.
Plus the fault code that came up first time around was directly related to the compressor.

fingers crossed now.