Ask around all your shooting pals. I bet there's one or two with a shotgun languishing in a cabinet taking up space needed for another rifle, or to stop things banging into each other. York Guns? Fine establishment no doubt, but they will want their pound of flesh for everything you buy. Try a few smaller gun shops around, maybe in the country where those skinflint farmers will take their shotguns. They are more likely to have something cheap and cheerful. (Just walk in with your trousers held up with bailing twine).
If you get the chance of a cheap gun, there's a few checks to do on it. First of all, check the barrels are straight, no bulges, and look inside the barrels to check there's nothing amiss there. Ensure the top rib is fixed on properly. Take the fore-end off and try to wiggle the barrels about. Should be nice and solid, if there's any play, give that one a pass. If it's supposed to be an ejector, check they work. (ejectors are nice to have, but by no means essential and non-ejectors are always cheaper). Especially with older guns, check the stock hasn't got any cracks in it. Most likely place is behind the action at the thinnest part of the grip.