Spot on, I want to keep the rns510 to put in the golf R.
I've just been offered a rcd310 for £70 delivered so it looks like I may have sorted the problem.
Lets hope you get the radio code with this RCD310 your thinking of buying else you will be stuffed. You will also need the radio code for your RNS510 if you want to fit it in another vehicle. It looks like a trip to the dealer for your radio code.
I just thought you want to swap your RNS510 for a RCD310, I have my radio code and I would have done you a swap.