Pondoro Taylor used his 455 Webley to drop a lion and a hyena that were marauding around camp at night and while he didn't wear the big revolver when hunting he did keep it handy when in camp.

Like 9.3x57, I too used a lot of the Lyman 454190 cast bullets in my 4" barreled Webley Mk VI and killed quite a bit of game with it; rabbits, possums, hares, a couple of red deer and numerous feral goats. Once had a bunch of goats inside a live deer capture trap, a fenced area of land with plenty of cover and the gate dropped. Owner of trap wanted the goats dispatched so went to it with the Webley. Had to stalk around and got in a few headshots and the rest taken with chest and shoulder shots. My reloads in shortened 45 Colt cases with rims thinned were quite accurate and the 250gr flat pointed cast slug worked well.
Also shot a farm cattle beast that had sustained a broken leg out in some rough country, got to within 5 or so yards of the animal in the scrub and dropped it cold with a head shot from the Webley.

While I wouldn't expect to stop a charge from a large animal with a Webley 455, unless a head shot could be got in, I would sooner have the big reliable Webley to hand than anything smaller in the handgun field.