I I have now heard from Dr. Nicholas Harlow, the Purdey Archivist and Historian and with his kind permission quote him as follows:-
“That is an interesting discussion indeed. I did cover the Purdey production of Sniper rifles for the Journal (Vol 5, No. 1) in 2019, and so that has everythng I was aware of at that date. When I was doing the research, I never came across an invoice to Sir Abe Bailey directly for sniper rifles, and in some ways I don't think I ever could. From what I understand from Martin Pegler, seemingly backed up by our accounts, once any existing scopes in hand were used up all UK production was routed through the military. This means that it would have been impossible for Purdey to obtain scopes for a 'private purchase' order. I think that it is more likely that Bailey requested rifles from those that we had setup, and paid the British government for them, which could explain why Methven got to keep his.
I hope that makes sense as a theory. What I can confirm is that, as far as I am aware, there was no record kept of the serial numbers of the rifles that we worked on, and so I cannot confirm the provenance of individual rifles”
The Journal to which he refers is that of the Historical Breechloading Smallarms Association (HBSA)