I'll add that in my experience, which is currently somewhat limited, Irish sessions in England seem to be slowly dwindling at the moment- a combination of pub closures, aggressive Sky TV, bistroisation, inept and uninterested landlords, and perhaps a reduction in migration from Ireland.

My memories of Irish pubs in the 70s/ early 80s are that if there was live music, it was likely to be either showbands, Irish and Western, or rather selfconsciously organised and curated trad sessions with a good deal of Comhltas about them. That would be rural- I also remember some cracking stuff in Cork city.

Quite right about GHB- there are other Scottish pipes and excellent they are too- but they were pretty uncommon until relatively lately. I can't remember seeing them in the wild before the late 80s. Back in the 70s, Pack Dyer in Manchester had a set of pipes- I can't remember whether GHB or Brian Boru- which he very occasionally brought out and played setpieces on. He'd thinned down the reeds to tame them a bit.

But back to the Scottish sessions. One point that comes to mind is that back in the day, Scottish city pubs could be pretty desperate places, and landlords might not have taken kindly to activities that got in the way of drinking.