I just received this email from Atkin, Grant & Lang:
Good Afternoon Mr Addison,

Thank you for the email. The gun was finished and sold on May 7th, 1943. It is a bit of a peculiar gun; there were 3 others that were made roughly the same with the 2" chambers at the same time but for different clients. Your particular gun was made for Major R.K. Davey.

Kind
Regards
Karli Dunstan
Club & Marketing Coordinator

Gerry Addison