Odd fault Disco 3

My wife used 05 plate disco 3 2.7 HSE auto last saturday. on arrival home she informed me that the car was unstable and there was warning lights on dash. Next morning I noticed car was right down on suspension so grabbed my keys and started it, it rose to normal height and I drove it about 10 miles and all was fine. Later my wife using her keys got in it and all the warnings were on again, ie. display reads "HDC FAULT SYSTEM NOT AVAILABLE" also DSC light and Brake warning lamps are on and suspension stays down even when driving. This only happens when using one set of keys, everything ok when using other set. Any ideas. (sorry to waffle on)