Yes Red, IIRC you have that very nice, suppressed .410. Something which you guys seem to get a lot easier than us is a sound suppressor. For us it's a $200 tax, a background check, and a one year wait on the Federal paperwork, provided that your state even allows it. Only recently have they even been made legal for hunting in only a few states, like Texas.
At the local Walmart, a good wind sock on what the locals shoot, I actually found small amounts of 10ga, some .410, some 28 gauge. The lead shot ban kept the 10ga alive. Here too, the 16ga is an obsolete cartridge but there are a number of old guns floating around chambered for it, so the ammo and components can be had if one looks. They had only a bit more 20ga, but the vast majority of everything was 12ga.
The 28ga was obscure here but it was resurrected by trap shooters and upland bird hunters. It's still a rare gauge when you try and buy it, which is too bad because it's a pleasure to shoot.
Most of the shotguns I've seen in use hunting here are pumps and semis. The issue for selecting a hunting shotgun here is typically more a matter of cost, not firepower, because when you are hunting you have to drop in a magazine plug so it can hold no more than 2 rounds. A double barrel over here, either side by side or over under, costs a lot more than a pump. For example, you can get a Mossberg Maverick 88 12ga pump that has a 28" barrel with a vent rib that can use interchangeable chokes for about $190 new, which about £127. That is less than half the cost of a not too fancy Brazilian made side by side or a basic model of a Turkish made over-under, and a fraction of the cost of something nicer.
However, when you see a double barrel break action over here, it's usually an over-under more often than not. You don't see a lot of side by sides in use too much. What I have noticed is that when you see a double barrel here it's typically someone who's plunked down some serious cash on something nice, like a Ruger, a Beretta, a Browning, etc.
A fair number of people around here also still hunt with single shot break actions, like the H&R Topper. My main 12ga is a Mossberg pump, but the .410 I use a lot is an ancient Winchester model 37 single shot break action.
The H&R Topper/Pardner 12ga single shot has gained something of cult following amongst many bushcrafter types over here. Those single shots are not that expensive, lots are available used, they are rugged, reliable, and versatile. Check out the Pathfinder School on YouTube and they have done a lot with merging the H&R single shot into bushcraft.