Thanks, Leon. I've been chatting offline with the forum members who would be most likely to have suggestions (confirmed by only one response in this thread
) and I'll be posting 'before and after' pics in the next week or two. I'm still on the fence about using water to get out the warpage, but it's good I have someone agreeing with the idea - thanks.
I found a load of stuff by googling - interestingly, almost all of the sites started by promising to rescue your old prints, getting out creases, adding imagery to missing spots, etc., and every single one of these sites was ultimately referring to digital restoration. There were two that were bafflingly elusive, leaving only hints that they were referring to digital. Bottom line - if you have Photoshop, you can do all that stuff yourself.