I don't have a pic of it Frosty, but it looks exactly like the Webley Mk. VI here...... http://world.guns.ru/handguns/hg91-e.htm
The Mk.VI was manufactured by Webley from 1915 until 1921, after which it was manufactured by the Royal Small Arms Factory at Enfield Lock....until about 1932.
A lot of 'em were imported in the '50's and '60's. The importer had them modified (had the rear of the cylinder turned down a few thou) to use with .45ACP with halfmoon clips.
At that time they sold for around $35-$45. I paid $45 for mine in the mid-'70's.
Theoretically, the .455 should require a .454 bullet, but I slugged my barrel and it's .4515......same as my 1911's, so reloading for it is easy.
And, no, it's not for sale.