Little update - it looks like I won't need to name and shame the high street retailer who sold me a used TomTom GO 510 as "new": they replaced it and I upgraded (for an extra £40) to the 710 as they "didn't have any more 510s in stock" (uh huh? Riiight...).
The not-connecting thing seems to have been resolved by installing the TomTom Home software in an administrative account, but I'm still having the problem with settings being deleted every time I dock the TomTom on the Mac. I'm going to give the PC version a try, but I don't know for sure if my Windows box has any USB 2 ports on it (I've never needed them as it's only a file server).
Another problem on the OS X version of the TomTom Home software: I can't use the "My TomTom GO 710" option to plan routes (or do anything at all) on - it just says something along the lines of "A required component is not available...". :(
The Bluetooth problems I was having - where I could only connect to my Motorola once and then the TomTom wouldn't connect again - seem to have been fixed by installing an app from the TomTom support site called "Clear Flash".
Still, on the plus side, the iPod control works brilliantly, and I now have an extra carry case and home dock.Hell, I think it will even navigate me to places using this new-fangled GPS technology I keep seeing mentioned...
/al - happier bunny...
