No he deleted it. When I asked for a copy he refused saying that it's not in the public domain. To be honest I was ok with that as I was grateful for the effort he put in to recover the router. He's a clever guy.
There was one little minor problem with the router password which was set to "admin", But the change password page required entry of the current password to be at least six digits because in the original firmware it would have been a long string of digits.
I didn't have a clue how to fix it but after mentioning it he came back within half an hour with a screenshot of the page with the brower debug on, and highlighting two limit numbers in the HTML code that I needed to override to allow the admin pw to be accepted. It's something I'd have to do after any future factory reset so I saved it for future reference.