Thanks Quin1965, I have tried a few of the things you suggested, but changing the navcore doesn't seem to make any difference, even your DSA ones..
I read somewhere once about someone changing a battery and breaking the resistor to the top right, I have checked and this seems fine, but this is probably a hardware issue Methinks..
Thanks anyway....
If anyone out there can point me in the right direction of which is the Bluetooth chip or a schematric of the go520 (I kinda doubt that) I would be very grateful.