makecoldplayhistory » In Win 10's copy/paste, you'll get the option like "rename any that have a duplicate name" and it'll add a (1) at the end.
In which case I'd end up with a lot of duplicate files which I don't want to sort out by hand. Though thanks for all the other ideas - I think there's something there which will work. Though kind of prompted by Colin last night I think I might drop into Linux and use scripting stuff - apart from anything else I realised I'm also not entirely sure where all the backups are so want to search for files in all locations on all the multiple disks I have, and it's straightforward to generate a list of locations for a manual search that way. Good point about checking creation dates as well - that should be sufficient to determine identical photos.
