Hi Ballebar,
Many thanks for the help. I got the PM with the number and have tried it. But again it does not work. One thing I have discovered is that the unlock file is empty after having tried it. I thought I had made a mistake first and not saved it so did it all again. But it seems to be normal that if the unlock code is not valid that it deletes it. I did try checking the number and there was some white space after the number so removed it - but again no luck. I also revisited the sd card using the diagnostics menu. There is a serial number but it is only 5 numbers (62154) and I was under the impression that the instructions on another page here explicitly said this was not the number and it had to be 10 digits. I did try using this 5 digit number in Jetmouse and it did not reject it and generated a number. Unfortunately this code also did not unlock the maps and when I checked afterwards was also missing from the unlock file. I appreciate this is all rather unknown and a bit trial and error, so I am not sure if you have any new ideas? Has anyone actually managed to unlock these maps?