I've thought about it a tick & about the only possibility for Purdey to apply the APUN would be under the umbrella of a tube maker being an authorized outlet of Whitworth steel tubes. Too many outlets would be difficult to track the royalties. Unless you can show me in an entry in a ledger, Purdey was no different than any other continental maker and was sourcing their tubes, so for now I find it difficult to see that Purdey was applying APUN numbers. As always, follow the money.
Kind Regards,
Raimey
rse
