147 built in sat nav on the blink

hello everyone,
wandering if anyone could give me some advice. ive got a 2003 model 147, with the built in sat nav unit (the one that controls the radio/sat nav/ trip computer etc)

yesterday morning it went on the blink. when i start the car, the alfa logo comes on, and then it seems to crash and try and restart again. it just keeps doing this. so it wont boot up, the radio and sat nav wont work.

has anyone come accross this before? ive called alfa customer care, but they know nothing. ive rung my local ancaster service centre, but they are worse than useless (suggested taking out the unit and replcaing for £1500 - they 'dont work on those things')

any help or advice? ive seen some posts on another site about a weak battery causing other electrical faults. is this likely?

thanks in advance for any help!!!