I take it they're not limited to just the UK then?
Correct, they are in The Netherlands too and I do not complain about my speed on coax I rarely do after ditching fiber which was 500 even 1000Mbps where I could only reach 200Mbps outside the isp's and sometimes on the fiber isp's network I was lucky to reach 500Mbps the technicians couldn't find the problem onsite even took the fiber box off my wall and took it to the fiber station where all the fiber gets send out and connected it there to find the same problem. Less than a week after the fiber other started their troubleshooting it came back the centrals capacity was only 10Gbit which was an issue when they mostly sell 1gigbit up and down and promise 900/900
So I went coax instead 1000/500 Mbps cheaper than fiber only about 42USD where gigabit fiber is about 56,26USD.
My isp promises 800/500 Mbps and I do over 900Mbps down on cable 24/7 so I do not really complain I just need a stronger tiny server (i5-8500T) because it can only pull 600/300Mbps.
This is why I do not want to try fiber even Bahnhof offers 1/1Gbit for about 14USD a month for 6 months than the price goes up to 49USD, but it's a open-net shared fiber solution not p2p and after the fiber owner went from P2P to Open-net this where all their problems at least for me and others started.
@TheLostSwede is their fiber P2P or Open-net?