Tom Tom Mobile on 6600 why does it hate brighton?

Hi,
Running Tom Tom 5 on the supplied 126mb mmc card.
All's well and good until I plan a journey around a 20-50 mile radius of brighton at which point it flips over to the map with the reading routes bar on the bottom of the screen then tom tom closes and I get a app closed message.
It's all a touch annoyng as I travel around the south east. When planning more distant routes (>50miles)or closer routes (<20 miles) then it works fine.
Any ideas

[philtenant]

Hi. I'm running TT5 mobile on same phone as you and I also live in same neck of the wood. No problems with mine all ok doesn't seem to matter on distance. Mine is on a 512mb card and I have Europe maps as well. Can't think of a good reason have you been through entire menu on app on phone to see if prefs have been set up wrong??