I own a Russian Nagant 1895, which your link shows a picture of. The Nagant is much different than the Webley in a number of ways. First of all, the Nagant is noticeably smaller if you were to put it side by side to the Webley. The Nagant is more the size of a S&W .38 Victory, which I also have. The cartridge for the Nagant is smaller and not produced anymore, save one specialty maker that I'm aware of, and I haven't heard the best reviews of it, either.
The loading is also completely different. The Webley is a top break revolver, meaning the whole top of the gun opens, or "breaks" forward, exposing the cylinder. The Nagant, on the other hand, is extremely awkward to load. First, you pull the pin underneath the barrel forward. Next, you twist the ring it's on (which surrounds the barrel) to the side. On the opposite side of the gun is a lever to the side of the cylinder which you flip down, which exposes a single chamber. you then push the pin back in, which now lines up with the chamber and is used as a rod to shove the spent shell back out. You can then load in a fresh bullet, and then proceed to do this five more times until you're fully loaded, then flipping the chamber cover back up, twisting the rod back underneath the barrel and pushing back into its resting spot. If, by that time, you haven't already been shot, killed, and burried, you are free to proceed firing the gun. Needless to say, it's a very ineficient loader.
The trigger pull is also VERY heavy, which means it'll likely affect your aim.
I think the Nagant is an interesting revolver, but I don't think it comes anywhere close to being a close enough for a Webley.
That said, your best bet for a close enough would be the Enfiled No. 2 Mk 1:
http://world.guns.ru/handguns/hg92-e.htm It's essentially a Webley in a .38. Apart from some minor differences, it's essentially the same gun and loads exactly the same. You can find the Enfield revolvers cheaper than the Webleys. You can find blank firing models of this gun for even cheaper.