There is a company called
RSW Solutions. They have written software that can interact with the air suspension on RRs. Classics with EAS and the P38s, and probably onwards.
There are instructions for creating your own cables or you can buy them made up online.
I'm helping a friend with his P38 suspension at the moment but I'm very new to this stuff, however I've got a RRC with EAS to play with for a week to hopefully help me out.
If you're in the area of Coventry then perhaps we could meet up one evening? I've got the cable, software and laptop but so far have only tried it on one vehicle...