Disco series 2, air supenssion on one side lifted to it absolute max, the only way I could get it down was to lossed off the air feed at the compressor to the Air Suspension unit. when engine stated up again it lifted again. So i have now plugged out the comprressor unit and the 2 solenoids .
Does this sound like a faulty air suspension height sensor?

very much so, change it before it goes bang on the motorway and kills you...

read this: http://www.landyzone.co.uk/lz/f38/disco-ii-air-suspension-definitive-guide-61211.html