Mr. Cartmell:
Deciphering what I can from the few photos I've seen, this very-light non-ejector is early in Skimin & Wood's 2-inch production, likely from 1930. I don't yet see the JA mark on this guns barrel flats (at least from what I can make out).
In the book, Birmingham Gunmakers, by Douglas Tate, pgs. 100-104, Skimin & Wood; he states that in the Birmingham quarter, an “entrepreneurial gunmaker businessman or provincial gunmaker often used self employed specialists and outworkers in a gun’s construction. He goes on to state, Skimin had used Joseph Asbury, an actionmaker in Lench Street to make up 20 bore actions to fit 12 bore faces for their lightweight 2 inch 12 bore shotguns. States that the guns were offered finished to the trade “Wholesale Only” in August 1930. States some of Skimin & Wood clients for these guns included, Graham of Inverness, MacPhersons of Inverness, Kimball Arms in the USA, Linsley Brothers and C.S. Rosson.
Also, in 'British Gunmakers', Volume Two - Birmingham, Scotland & the Regions, by Nigel Brown, pg. 139, under CS Rosson it states, "In the years before the Second World War Rosson, like many small gunmaking businesses started having a number of their guns made up for them to their specifications by the trade. Most of them were in fact built by Joseph Curry of New House Lane, Whittall Street and in many cases using high quality Joseph Asbury action and barrel machinings. The J A initials to be found stamped on the barrels of a number of Rosson guns of that period confirming their origins." Joseph Curry of Birmingham is listed as being a Gun Finisher by trade, in business 1912-1950, as stated within Nigel Brown’s aforementioned book.
So who made what and who turned the screw?