I concur with the Hippo....
Regardless of air strut fitment, the system measures height using a sensor mounted to a suspension arm so regardless of air strut it measures the phsyical height from the suspension components.....
As above check the sensor fitment and wiring....
When I bought mine, the previous owner had the system calibrated to sit 1" lower than normal - I had it recalibrated at a Land Rover dealer to ride correctly and took about 20 minutes (the original charge was £108 - but as they only took 20 minutes the guy felt embarrased to charge me the full whack so we settled on £65)
London is a big place, a little more detail required as there maybe someone with the All Comms or other plug in device local to you who can recalibrate for you....
Or if you intend to keep the car, get the All Comms software and lead or one of the other diagnostic devices as it will save you in the long run....
Just like Hippo, I invested in the RSW Solutions All Comms and it has been very useful thus far.....
I bought it direct from the Legend and Genius that is Storey Wilson (he is an American who has devoted an immense amount of his time in developing the All Comms system in amongst his regular job) so was shipped over from the States, took 12 days, cost me £155 for the All Comms, £24 delivery and £16 import and VAT charges, so about £185-£190.
If you have more money in the bank, you could try one of Blackbox Solutions units (Nanocom or Faultmate Extreme), the GAP Diagnostics IIDTool or the Bearmach Hawkeye.
