Bit of an updated, took the RR over to his mechanic, put it on his snap on diagnostic machine, a couple of faults came up;
low voltage
solenoid ( not sure which one )
The transmission temp was around 100 degrees, not sure if this is good or bad.
Anyway this didn't really solve anything so he took it for a test drive and sure enough he felt this vibration, so he spoke to the dealer with the view that it should go for a more in depth test. The dealer is arranging for it to go into a local LR garage for a full diagnostic check and so what that says.