Tried a couple of different cords for two hours each and no-joy. Assume the battery is sealed in the case as I don't see a quick way to access the interior??
I assume that was two hours each on an AC charger (not vehicle?). Unless the battery is toast, that's not good. Might be worth a shot to replace it if you want to try to recover your device.
The battery can be a bit of a trick to access, but all of the cases do come apart. It's typically a matter of finding the two torx head screws that must be removed to separate the case.
FWIW, your device is also known as a Via 1505 when you're out looking.
I've never used NewPower99, but they do have something that shows you how the process works:
TomTom Via 1505M Battery Replacement Kit. Comes with Tools, Video Instructions, Extended Life Battery and Full ONE YEAR WARRANTY
newpower99.com
That page also includes a YouTube video that gives the basics of replacement.
I've tended to go with batteryship.com. This appears to be the battery for the Via 1505:
I'd disassemble it first using the video and take a meter to it. If you can manage to get a couple of straight pins into the connector, I would be interested to know what the voltage is between red and black wires. Can decide what to do from there.