Francis:
I did indeed see all. Anyone think a Russian pigeon gun? One of a couple. Letter on the safety makes me think Russian or one for some Bohemian pigeon shooter.

Tough question on end of the Whitworth there Francis. Ah, I would say the late 1930s would see the end of the supply. Armstrong absorbed Whitworth and in 1927 Vickers vacuumed the whole lot. From tube steel examples, I'm lead to believe that Vickers phased out the availability of Whitworth and offered their own variant. Rampant speculation for the moment.

Kind Regards,

Raimey
rse