Terry came to me today and I can add more info
Gateway is not the Problem as his Gateway was a 1K0907530L and the RNS doesn't go into sleep mode
I tried a newer AF gateway, different RNS and new ignition switch all made no difference to the draw on the RNS
There were several faults with the locking system and one in the steering ignition switch (why I tried a new switch)
I'm thinking it is to do with the locking system why the RNS doesn't shutdown