Hello
I have been down this avenue myself. The TV will not pick up PAL signals, the box needs a converter, I believe they are about 40 quid. Personally I am waiting to obtain a PAL/NTSC dvd player to go into the boot. My paticular tuner in the boot has a line in feed for players etc.
No translation software for the MMCS unit exists, the language itself is not contained on the Navigation CD but rather on a rom within the MMCS unit itself. Unless you know how to flash the ROM to a UK script, that idea is probably a no-starter.
I did find out however, and this may be an avenue that some may wish to persue, that the map disks are not made by Mitsubishi, but by Pioneer as part of their carrozzeria sat-nav software. I see no reason why a UK copy of this software would not give you UK streets. Then of course its only a matter of working out the Japanese script, which as I have said already is embedded within the MMCS unit.
For lots more information on this and other Galant/Legnum/VR4 queries, have a look at the forums on
http://www.clubvr4.com/ search for 'mmcs' and you'll see some of the extensive reasearch that has gone into this.