Got my RNS510 installed this morning, looks brilliant.
Just an update on the DAB, although I am not sure which version I have (no idea how to check), I have the DAB option.
Basically what you need to is hold down the 'set-up' button when you turn the unit on and after a few seconds a menu will appear, which gives a list of radio options.
I need to speak to Darren who supplied me the unit to ask what version this is and whether the DAB will actually work if a DAB aerial is plugged in.