Yes,
Webley revolvers have been "broken" when over stressed by continual firing of .45 acp rounds.
The ACP is as hot or hotter than the proof round for the .455 caliber.
That said many have been fired for years with .45acp and still exist- though I don't recommend nor do I fire .45acp in a Webley.
I would not buy one that has been cut with intention of firing it either, you have no way to know how many rounds of .45acp have already been fired it it and it may be a the point of failure.
Cost/price you can find by looking at the online auctions; they do vary quite a bit.
You may have seen this picture or similar ones before.
