@davetranter
Yeah, that's a point regarding systems failures / power cuts.
There are some combi-boilers used here, but they're definitely not the norm. They'd be more a feature of very small flats or some very old victorian-era houses that had instantaneous hot water retrofitted to them as a cheap way of doing a proper hot water system.
There were a *LOT* of complaints about them during the 'big freeze' extreme winter we had a few years ago. Much like the UK, we had absolutely unprecedented cold weather back in 2010. It was the coldest winter in 130 years.
The problem was that a lot of mains water pipes running from the deeper street-level mains to individual properties were never designed for -17ºC.
This part of Ireland rarely even gets frost! Much like parts of Devon and Cornwall's coasts we can grow palm trees

So, a lot of water mains froze solid or cracked when they thawed.
The result of that was that some people who had combiboiler heating systems were unable to safely run their systems at all and had to be evacuated out of their homes as it was too cold. The systems were unable to run safely without a supply of mains water, or were designed to trip-out if there was no mains pressure so they were left with no heat!!
That's led to a bit of a re-think about fitting them as the more 'traditional' pressurised hydronic systems worked perfectly. A lot of social housing units that might have had such systems have had them modified, especially where there's an old / vulnerable resident.
There were also a lot of issues with attic tanks flooding houses (which I think was the case in the UK too). This was mostly where unoccupied houses (people on holidays / empty new build etc) had attic tanks freeze and pipes burst and completely wreck homes.
So, all in all I'd have to say that Irish and British style plumbing's FAR from winter-hardened stuff!
If weather gets more extreme and those kinds of winters become a regular occurrence, I think both countries are going to need a bit of a re-think about how plumbing's done.