Curtis Clay about a different coin: "...three branch mints, clearly official, that produced large issues of sestertii, and some middle bronze too, two of which Laffranchi pointed out in his important article of 1948, while I discovered the third myself in my work on Claudius, which began as a Numismatic Chronicle review of von Kaenel's Münzprägung des Claudius.
That is, a Spanish mint, which furnished all of the sestertii and dupondii in the Pobla de Mafumet hoard; a Gallic mint, whose sestertii were often countermarked PROB; and a fine-style mint, my discovery, perhaps located in the Po valley.
There is an important article on Claudian bronzes of western provincial style in Revue Numismatique of around 2004, which might cover your coin. I have looked at the text online, but the plates are NOT online so I don't know what exact series and styles it deals with.
I think the major cause of the branch mint production and imitations in bronze under Claudius was not his invasion of Britain in 43, but his attempt to restrike as much of Caligula's coinage as possible in 41 AD. That's why virtually all of the branch-mint coins and imitations omit P P, so ought to have been produced before Jan. 42 when Claudius accepted that title."
"An important article on the subject in the Revue Numismatique by P.H. Besombes and J.N. Barrandon (Nouvelles propositions de classement des monnaies de « bronze » de Claude Ier, RN 2000) have identified official mints as:
- Rome
- Spain I (mint in military camp, Leon region, Astorga), dedicated to the military units in Spain
- Spain II (Tarraco), known from the La Pobla de Mafumet hoard
- Gaul (Lugdunum?)
many unofficial local imitations being made at this time in Gaul (up to 30 to 50% of the Claudius coinage found ...)"