Well worth checking out your local auction house. The nearest one to me is Mitchells at Cockermouth in Cumbria. They have a sporting sale twice a year. Fishing paraphernalia, stuffed animals and birds, leg of mutton shotgun holders, the odd lot of cartridges, some sporting rifles, air guns, paintings of country scenes, the type of stuff you'd expect when an old farmer passes on. You can go along before the auction and have a look at the guns and handle them, so at least you can check them to a certain degree, have a squint down the barrel, check the action and in the case of shotguns how tight it is and whether the ejectors work (bring a couple of snap caps along).
Many of the lots will be old guns that have been propped up behind a farmer's back door for eventualities for the last 50 years and will have seen better days. But you do get some hidden gems, the odd good quality old English gun or an AYA No. 2 or something similar. Certainly worth popping along for the odd half hour to see if there's anything interesting.