Well, funnily enough...
Mine seems to have sprung to life too. Using the aftermarket aerial! Still only shows a couple of satellites on the settings however have tried it a few times and it's correctly identified my position. I did change the time setting on it, not sure if that helped.
Will probably try taking the boot aerial apart at some point in the next few days to see if I can make it work in an OEM fashion
Expect the satellite reception will be better with an external aerial.