Dear Equest, Sorry to pour cold water over your head, the Japanese GPS by Denso will not work in the UK, it is specifically meant for the Japanese market. I bought a similar car model year 2005, only managed to get the radio and TV to work ordering the components from the UK.
The rest of the multifunction monitor works e.g. the fuel/speed/air con/reverse camera/Telephone numbers/Bluetooth/etc etc computers but you will have to link the Japanese text to the UK, that's where the UK manual comes in very useful....
You can download an English manual for the US petrol version from here...
Download PDF Toyota Land Cruiser 1998 - 2007 Service Manual | PDFTown.com. Don't buy CD from UK as most just are downloads from the site given and selling them by adding some extra rubbish. (My experience!). The difference is the engine of course.
Some things are exclusively Japanese e.g. cruise control max. speed limit is 110 kph, (have not been able to reset that yet).
Other than the slight inconveniences, I have been enjoying my car, have so far driven 47,000km after owning it for a year. Still love it and (touch wood) no problems so far..... Hope you enjoy yours