Watson's revolver?

I recently bought "The Sherlock Holmes Collection," the only surviving BBC episodes starring Peter Cushing. These five 1960s episodes have Watson carrying and using "his service revolver." Seeing him load it in "A Study in Scarlet" shows it to be a solid frame, gate loader. I have no idea what its brand and model are. Since its appearance is odd, I guess it's possible that it is not a standard revolver at all. Rather, it could be something that has been cobbled together, perhaps for an earlier production. What I postulate is something similar to the double action revolver in the 1950s children's cowboy series, "Annie Oakley," starring Gail Davis, that was altered to look like a Colt Single Action Army.

Anyone who can shed light on Watson's strange revolver, please do.

Webley RIC?
https://en.wikipedia.org/wiki/Webley_Revolver

In the series starring Peter Cushing, the revolver was definitely not an RIC or top break.

Beaumont Adams would fit the bill. The orginal like the one shown were cap and ball, but later cartridge conversions were used



Article seen here makes mention of an Adams

The revolver is a 6.5-barreled Adams 450.

The gun in question.....sorry for the bad pic...