Finally had some time to try and dig into this a little further.

The car definitely goes to sleep (orange light on gear shift next to P goes out) and the nav unit is definitely staying on permanently.

I measured drain, once the car sleeps it dropped to about 0.65A (with the nav unit red light still on / blinking).

I disconnected the mk4 DVD nav and then it drops to 0.2A and stays there. I tried pulling other fuses (72,73,74,75) for the audio/ telephone/nav modules but the current didn’t drop any further.

Is 0.2A about right or does this seem high still?

I guess I can try and replace the nav module but I’m guessing its possible something else is keeping the nav awake and the nav is actually fine?