Tomtom Rider Users Near Crewe?

Hi
I posted before about problems charging my TomTom Rider 400 whilst on the bike - works fine via USB charger.
To date TomTom have replaced the mounting dock and also tested the unit, replacing the battery as the cause of the problem.
I also had an autoelectrican check my switched live feed to ensure the feed to the dock to make sure everything was connected properly.
So the 'repaired' unit arrives back, I mount it on the dock and hey, ho - still not charging!

Before I go back to TomTom again - does anyone out there have a functioning TomTom which I could check against - this is driving me mad!

Russ

(2005 Daytona 955i)