Strange first post I will grant you.
Thoroughly enjoying my MY12 and getting used to its little ways.
However I use the sat nav. a lot and I have found that the last two mornings I have gone to input a post code only to discover that the machine thinks I have moved to Belgium (I'm in Kent!). I need to go to the address entry instead then change the country and then it all works OK.
I reset the defaults but it happened again, am I missing something?
I did set my "home" as my home post code so it presumably knows that I call GBR "home"?

Have you had a particularly low battery. It resets to Belgium as default, on the older systems when you put a new disk in that updated the satnav systems it would always do this.
I suspect that when you start the engine, it drains the power enough to just reset the vehicle Ecu's.

Under warranty though, I'd be wanting them to investigate further.

Check the battery connections as well.  Bodsys Brake Bible
Software Updates Contact me
RRS Timed Heat/Remote kits - Contact me
BAS Engine Re-maps/ EGR Blank EuIII and EuIV
Clock On The Dash/ SNOTM /3Flash / BT Update /Service Reset/Error Codes read\ Gearbox Reset
See it HERE

Come on Belgium!