if you have a switch on the right (you're in the UK so I'm assuming right-hand drive) with three green lights next to the headlight control then you have the adjustable full air suspension, if not you just have auto-leveling rear suspension, which just compensates for heavy loads

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2006 BMW X5 4.8is Lemans Blue/Beige/Dark Maple
-Nav, Comfort Seats, Heated Steering Wheel,
Rear Airbags, AUX Input
2009 BMW M3 Space Grey/Black/Carbon
-all options