My UK mobile phone provider blocks it, presumably unless I tell them I want adult filtering off

Why haven't you told them that?

I honestly can't be arsed, I have a VPN so I switch that on if I come across blocked links.

You should do it. Slightly increase the cost to them of having this default filter.

They banned all of Finland, presumably due to a spat with a Finnish blogger, although the story seems a bit murky.

https://lobste.rs/s/z0mdor/archive_today_is_directing_ddos_a...