Hi AGS,
Just a couple of thoughts: I expect you know that the Army and Navy Co-operative Society was started as a wholesaler of all types of goods for military personnel ONLY. Later it was opened up to the Civil Service employees, and later still just became a normal store with department stores in major British cities, such as Guildford (near Bisley) where i would go shopping in the 1980s and 1990s.
This group of stores began to lose money and was bought out by a rival group, the House of Fraser (not Frasure) based in Glasgow, so this is how the records have ended up in Glasgow, Scotland.
The Army & Navy Gun department certainly ordered guns in in batches and then sold them on when an officer asked for one, hence the ledgers. This is how their their prices were 25% or so less than 'proper' retail gunmakers.
Good luck with your further researches.
HB