'Sporting and General' are still in Shrewsbury, on Belle Vue Road. Expensive. Actually, a rip off. Won't touch them with a barge pole now, but that's just my view.
Cambers is good, but expensive - more used to selling to farmers who put guns on their business accounts so don't mind paying bit more.
Don't know about Feather and Fin. Heard of them. Think they are a small set up - at least regarding airguns. Minsterley Ranges also a few airguns and some dust covered pellet tins.
Morgans of Oswestry is the best I've seen in Shropshire - Used to be based at their main building supplies depot on Shrewsbury Road, but have now moved all fishing and shooting stuff to a new shop on, I think, Castle Street in Oswestry itself. Good range of guns (for Shropshire) and accessories, bit poor on pellets, but prices are good and always new stuff coming in.

Don't know of anything further south I'm afraid. Hope this helps.