I'm afraid to say you are wrong there Zac, I bought one off eBay, seller said It was faulty, replaced the Battery, Works Perfect, just waiting for a Battery for a Tomtom Go 500, this is very difficult to do.
It sounds easy by the instructions Zac, doing the job is far more trying as the Location of this Battery needs a lot of patience the right Torx screwdrivers & a very steady hand.
I'll add to this on Thurs when I insert the battery, the reason for the post, people sell them just because the battery fails, they are cheap to bye, & with patience you can save youself money by doing the job yourself.