So I bought the above items from eBay and spent around 2 hours fitting them and I now have Sync 3. The screen, APIM and aerial are all brand new, cost around £600, and were programmed specifically for my car’s configuration so everything works as it should. The USB hub and loom are seconds from a salvage yard. I didn’t have to remove the lower centre console, just the back of the armrest to get to the USB hub cabling. Also didn’t have to replace the whole loom – just a bit of soldering for the connector to power up the new hub. The GPS aerial is fitted inside the rear view mirror assembly so everything is nicely hidden away.
It’s also running version 3 firmware so should be more reliable.