I crewed in the 1976 Tempest Worlds at Association Island, US Sailing Center (at the time) Watertown, NY. Anybody remember it? The winning team was Swedish I think, and the crew was built like IGOR. Mostly I remember they raced naked, balls out. Never seen anything like it since and hope I never do. But my point is, if I had one, The Tempest. Thought they died, the boat not the crew, but I guess they live somewhere. Have to be more than a sportboat, so what about a sportboat?
We're I you guys in Ireland? Pick a local class unless you like day sailing the boat. There are tons of good fleets in Ireland. For the record, I am about the same as you two and I love my Tempest. They're an awful lot of fun in the breeze.
Crazy as it might seem, this morning I thought about this question and the following occurred to me.
Besides going with boat popular locally for racing or for general use (selling is easier) there is the simple fun factor, like beer cruises from port to port or pub to pub (it is an area that sustains lots of coastal communities) one can consider decent non keel rig or one that will retract keel, due to tides and in cruise case, make sure boat is one they can stand on at dockside or tied to buoy, etc.
All that aside, there is one wee craft that lends itself to both, but it is small: the hard to find and venerable Interclub (IC) dingy. A most wonderful little boat that seems, of all dinghies that come to mind, indifferent to weight and most easy to maintain. They need to come back to us in fleet form in all water.
Suckers are more fun than most realize...here is pic of a fleet sailing in Belmont Harbor, Chicago, IL, USA, in 1974, when men and women actually had fun frostbiting in wee boats in the Windy City (refers to political fog-horning).
I choose to race Solings on Boston Harbor because of my largish frame. It's another class with no future, but it has nice lines and is fun to sail. My criteria were local fleet and good race participation.
Possibly another thing to investigate is which class will most easily/legally allow for maximum CB area/lower center of effort to balance out the greater "hiking" moment. If I understand correctly, the 5O5 has fewer restrictions in CB design.
Soling is a wonderful boat, although I thought the Etchells finer...but spendy. I think it will be around a bit...but definitely not easy to rig or haul around and ramp launch. But, then, the US has jillions wonderful no future boats...110, Ensign, Tempest and long list.