I believe the pistol is a Webley, but I don't have ours on hand to compare.
That's right - almost certainly the .455 Mk. VI, given the ~6 inch barrel, square-based grips with thumb rest and distinctive removable front sight. It's not a 100% perfect representation (e.g. the yoke should be scalloped in front of the hinge, not straight all the way down) but on the whole a very nice use of a classic revolver.