Your extractor lever is probably too worn, where the ledge abuts the receiver, to slip past when it ought. Carefully stone it or replace it with a better one.
The old saying applies. If it ain't broke, DON"T FIX IT!My fellow Webley collector helped me to get my Webley Mk IV in .380 to retract the extractor once again. The problem in getting the hinge pin back into the frame was that this bushing, which has a smaller, spring-set bushing inside it, was "chipped" on one side--it made it difficult for the hinge pin to go through it. It is working now, and I won't disassemble it again for some time. All of my other Webleys are working fine. Thanks for all of the help. By the way, we couldn't find a reason for the extractor not resetting before.