The F and P Sounds in Wolf Pit

Where is woolpen? It's a village in the english county of east anglia. Where does the name woolpit come from? Does it have anything to do with sheep? You might guess that but no, it actually comes from the sheep's mane predator, the wolf. A local people didn't wolves preying on their sheep and other livestock, so they dug deep pits to trap the wolves. They'd put a carcass of an animal down in the pit, and when the hungry wolves would go down to try to get a free lunch, they wouldn't be able to climb out again easily because of how deep and narrow the pits were. The two words blend together: Wolf