I believe the weapon is actually a Vesely V42,produce @1942 by BSA.
It used a unique double column magazine in 9mm.The rounds were loaded in tandem with the front column
being fired first.Didn't work and wasn't adopted.See "Military Small Arms of the Twentieth Century",Hogg and Weeks,1973,pgs 2.45 and 2.46.
The one photo appears to show engraving saying
"TO THE GENERAL
CAM BROWNING CB DSO
FROM VAP HOLDINGS"
Near as I can make out.