Hi Brian,
Sounds like you've got a MK1 Webley there Brian!
41180 is fairly late in the life of these. I don't have the exact dates (mine is even later: 42548) but they were made into the 50,000's and 1930s.
Your's at a guess I'd say is going to be around 1928-29.
I'm sure someone will have a list somewhere?
The 180 on the front is just a repeat of the last three digits of the serial number.
How about some pics of yours?
Best
Gene
P.S. Did you see I also got one recently:
http://www.airgunbbs.com/showthread....nt-and-advice!