Can anyone help with some suggestions regarding my Mk4 SatNav system?

I have upgraded the OS to V32 which includes a new splash screen, new sky image and new 3D pointers (all of which I used in my previous OS, V28).
I am also using 2009.1 (EUR) map disk.
The system worked fine today all the way to my destination which took about an hour. After about 15 minutes on my return home the sytem shut down completely, the splash screen appeared and then a message;

"Do you want to continue navigation?" This happened several times.

I selected both NO and YES at various times but the results were the same i.e. the split screen with map reappeared but the pointer was in the wrong position on the map and continued jumping to various incorrect positions, sometimes tracking north, sometimes locking to pointing north, with no satellite image in the top right corner of the screen. This restart happened six or seven times until finally the screen and unit completely locked up with split screen image still visible. The CD/Radio continued to work but with no effect on the locked split screen image. When I turned off the ignition and restarted the car the Splash Screen did not appear and the SatNav option was not available to choose.
I left the car for over two hours, switched on the ignition, initially the default screen appeared with no SatNav option but this was replaced after a few seconds with my splash screen and then by the split screen showing my correct position but the pointer showing the vehicle pointing West even though I know the vehicle is pointing South.

Any ideas anyone? I have a 1000 mile trip to do through Europe in a few weeks time and the thought of travelling without my (up to now) trusty SatNav is not a prospect I am happy with.

Nick.