Help identifying old Spanish revolver.

[Bob in Revelstoke]

I was recently given an old revolver that, when I first saw it I thought it was a S&W 3rd model Frontier. It is top break, 5 inch barrel with rib. As soon as I looked at the printing on the barrel rib much to my disappointment saw the words ABLA ALMANGE Y GA EIBAR ESPANIA. However, it was noted it had British proof marks, broad arrow over IH V5 F on the left side of the frame. Right side of frame marked TRADE
H
MARK
Left side of barrel crossed swords. Grips are black hard rubber, checkered with a large letter H in script. Cylinder holds 6 shots caliber .455 although it is not marked as such. Matching large letter H on right side of frame.

What few gun books I have didn't show anything. A GOOGLE search showed a picture of the same type of gun but nothing that could be matched to the letter H. They said Britain ordered thousands of revolvers in the 1st world war but most of them were rejected because of poor quality. Those that were accepted were proof marked.

The bore is bright and shiny with strong rifling and is quite accurate considering the very small military sights.

I don't know where else to look and thought perhaps someone here would know. Sending pictures is beyond my limited talents.

Thanks in advance
Bob