I was on the hunt for British and Commonwealth 'Pocket Field Service Pocket Books' and came across this great site with a great deal of info, not only of the Vickers MG, but of all sorts of other goodies. Worth a browse...
vickersmg.blog
Vickers MG Collection & Research Association
To advance the education of the public in the subject of military history and firearms, in particular (but not exclusively) in relation to the Vickers machine gun.
vickersmg.blog