Update - having spent a lot of time with Apple Support, the net outcome is, we are sorry there is nothing we can do, it’s over 30 days.
Looks like it was all of the app library data. I am now going to investigate software recovery as suggested. However I have come across some bad reviews online for some of these, along the lines of the software lists the files, you then buy the software, the software then tells you that the files are not recoverable.
Also of some concern, many of the software vendors when you dig deeper appear to be from the US or elsewhere, but are actually based in China…