I think if I was going for a new semi-auto, I would look at a Beretta first, in sporting configuration.

BUT as Dad has the Mossberg, I think removing all the rust, cutting the combi choke monstrosity off it, getting a exchangeable choke (Briley?) fitted to it, if still possible, and reblueing or just painting it green (!!!) might be what I will do in the first place. Even if over capitalising on possible one day resale value, will cost me less, and the pump action worked fast and well. Has a five shot magazine, so will still be C class legal under the new BS laws. And effective for the purpose I will own it for.

Later if I decide differently it could be disposed of, and something else replace it.

Need to get it transferred to my licence first and relatively quickly. New regulations might be in, in three or so months time.