Thanks for the help.
I managed to get it working without reverting back to 4.2. I connected up my old BB (the 8100) to 4.3 and it seemed to work. Then disconnected the 8100 and connected the 8110 and I didn't get the '...must be connected to internet...' message and went straight through to set up sync.
I am connected through a hub though (in my monitor) so maybe that was causing a few errors.
Anyway, all working now so thanks.