I’m not sure what to add to the question except perhaps why I am asking.
I find that various things whether it be a system upgrade or moving files or whatever tends to lose some settings, this just being one of them. If I know where it’s stored then I can be better at making sure they don’t get lost or unreadable etc. and save myself a significant amount of time.
Thanks @OttoKerner. I have a feeling there’s a little more to this mystery to go – mainly why a simple XML file is loosing information (if that is what is happening) but now that I have the location of the data I can keep an eye on it for next time these settings seem to reset to the defaults.