I was able to get this working so will answer my own enquiry, hopefully if someone comes along this will be helpful in the future.
I started out by accessing WindowsCE which runs behind the UI for the Head Unit, which has part number LAN1050EHGD
To do this you can:
1. Hold the Settings Cog button to access the firmware/bluetooth version info
2. Press and hold the centre of the screen for about 20 seconds to enter Test Mode (Dealer)
3. Enter the code 159357 to access Windows CE
Once inside Windows CE you can navigate using the Touchscreen to the Navigation App which should be under My Device/Storage Card4/NNG there is a program labelled MTX1200-GD called IGo Primo Motrex 1.1. Double Click on this to start the Navigation, and can then use the menus to change the time setting off "automatically set to GPS time"
To reset the headunit and get back to the normal UI menus either;
-find the file called LISA under the MyDevice/Storage Card/System folder
-or press the volume button and CD eject button whilst turning the volume down to reset the head unit
After this the Map and Nav buttons worked and could progress past the Agree screen