irish beer is an interesting thing. i think you guys likely get the picture, that ireland brewed basically stout/porter of the 1800s variety and pale ales comparable to england, no unmalted roasted barley in guinness until the late 20th century (pattinson). i have an interest in some of the strong ales like "
drogheda strong ale"
a MBAA podcast on guinness yeast indicates that guinness had spent considerable effort to analyze and maintain their yeast since the early 20th century. as well, wlp004/wy1084 is not simply a british yeast taken and used in dublin, but contains significant non-british genetic material, as well as what is described as "american".
the reality though is that earlier in history whiskey was the drink of choice in ireland apparently, all the porter and ale in general being a pretty modern thing.