Hello there Pabs - welcome to the forum … in part answer to your questions I can offer the following:
1: never heard key collectors referred to by any other name. I’d be interested if there is a specific name - if you find out pease post your findings.
2: none that I have found although several have some good pages. Check out the links noted on the form index, as well as http://www.deabath.com, an interesting story about the Blue Peter keys if nothing else.
3: there seems to be a lot of books about - check out Ebay’s French site and you’ll see a few nice glossy paged books there. I have not been fortunate enough to see any of these up close but they look interesting even if I can’t understand the text. The two books I have are: “Keys their history and collection” by Eric Monk and “Locks and Keys throughout the ages” by Vincent Eras. Both can be found on Ebay after a while.
I’ll keep watching your post to see if anyone else has further information to add - I’d be keen to find out more as well. Good luck with your collection - cheers for now Sarah