Update........
Bit strange, when first connected screen displayed in the menu 'Trip Computer' (I've got the IPK with this already in car), 'Set Up' etc etc with 'DSP' greyed out, six menu options in total (usually 4 with the old Rover one). Left it for 20-30 mins, back in car, no code required 'DSP' and 'Trip Computer' gone from menu and all working as normal....BUT no splash screen. I thought I'd get this when I swapped over to the B*W mk3 and would have to re flash with a Rover one??!!!
The Hi Line sat nav was a retrofit job about 18 months ago, all worked ok so didn't bother with T4, is this perhaps the reasons? Should I update the software?