It sounds like your NiMH Pack is reaching the end of its life, but there are a few ways to tell. I run a Mercedes garage, but have a sideline with the VX-1. I would be happy to take a look. We are in London, near dartford?
I too have a VX1 which is having problems. Can I give you a call as well? Mine is newer, and was working just fine. Then as I was driving the dashboard started going through what looked like a series of start-up procedures, all the lights flashed, and the speedo went all the way to the end, and back, but it did this 2-3 times and then died. Absolutely nothing works anymore. I tried the kill switch, I removed the front panels and pulled the connector out of the front CPU, thinking that would reboot it, but nothing.