Yes, that's the kind of thing. If you had an "add book" option in each county/region, you would be able to at least search (crudely) by looking under the area you are interested in. You might find the same book added under more than one area though, unless you added it to the highest level:

Example:

Aubrey Burl's "Guide to Stone Circles of Britain, Ireland and Brittany" would need to be added to some kind of higher level general database, as it covers much of the area covered by TMA (actually, the papery TMA is the same thing).

Chris Barber's "Ancient Stones of Wales" would need to be added to Wales rather than being added to, say, Powys and then again under different bits of Wales.

Craig Weatherhill's "Cornovia" would come under Cornwall (and/or Isles of Scilly), but his "Belerion" would be under Land's End Peninsula.

Books about the Peak District would cross Derbyshire and South Yorks!

I admit it's complicated, but it could be a really useful tool. A format for posting would need to be agreed and covered with submission guidelines, etc. Only multiple editions that include major revision/updates should be considered.