Was getting 'ride height only available' warnings following 'access' and then 'ride height' selection/operation. This would occur one or two minutes afterwards; shortly after that i would lose the acc as well. Same thing happened on two occasions after raising the suspension to go through flood water. I booked the car in for servicing at TH White's; shortly after the initial phone call i had two incidents of the sound not coming out of the speakers. This had happened on my previous rrs v6 and an ignition cycle had sorted it, but not this time. A detailed Q&A with one of the service engineers on the phone followed while the car was in the service bay. An updated down-load for the ICE and new compressor (under warantee tf ) seems to have fixed the problem . Total cost: £000.00
As always a very efficient service from THW.

Interesting (to me at least) was that i was told to keep a close eye on the problem and let them know if it occurred again - which i certainly would have done - but also seems to imply they weren't too sure if they had definitively fixed the problem...

Similar experience with my recently purchased MY12 RRS .........was getting intermittent amber warning messages of 'Normal Height Only Available' as well as 'Forward Alert Not Available' occurring together. Would disappear if restarted and sometimes would not show for days.
I took to dealers thinking it may be a loose wire on a sensor or something similar but I was surprised to be told that the suspension compressor needs replacing. This was done under warranty at no cost to me and thus far no further issues to date. Keeping fingers crossed now. 12MY RRS 3.0 SDV6 HSE Lux Sumatra / Black + contrast/ Grand Black
2010 Disco4 3.0 TDV6 HSE Nara Bronze - Missed very much
2008 Disco3 2.7 TDV6 XS Stornoway - Now gone

Sounds like the same problem I had Nottsman, i should have mentioned (just to be accurate!) my RRS is MY10 TDV8( ) HSE...Other than that problem-ette she's a beauty!