I grew up in the North. I live in the Midlands now. They're uncommon in both locations.

I just asked in my work chat, about a dozen Englishmen, based around Lancashire and Yorkshire; all have either a dryer or a washer-dryer; one guy in London has a washer-dryer. These are not rich people, just middle-class IT guys.

In my experience, the only flat I've rented that didn't have a dryer was a student hole in Preston that didn't have a washing machine either.

Maybe it's a sign of the times, maybe Lancashire is a cluster of dryer-lovers, but this is my anecdata.

Yes. Some houses have them and some don't. I'm also referring to mostly middle class people. I think the only thing that we can take from this thread of anecdata is that the following two statements are false:

"In the North literally every house has one."

"they've been ubiquitous since forever"

Clearly, neither of these things are true.