Here is a site that is mostly pictures and there are many very interesting ones there, however for the purpose of the exercise go to British, thence Webley and way down the bottom are patent specs and drawings for the Webley-Fosbery.
I only ever fired one, Adam, and it was a mnt cased example that belonged to a friend of mine , now deceased, so I suppose/hope that it now resides in someones's collection. It was an impressive piece of machinery.
Self Defence is not only a Right, it is an Obligation.