Ah, thanks. Experience had taught me not to lock myself into a mobile contract for such a long time. After a couple of years using EE, I switched to Three, getting far higher speeds (but worse latency).
Then Three became poor at home (the best base station was out of service. EE had been using that base, so it was bad too).
Then Three got that base up and running again, but EE is no longer using it.
I seem to be having to duck and dive to keep good service.
However, travelling around, I can say that EE has generally the best coverage of all the networks (my phone is on EE, so I can tell)
I'm hoping for good things when 5G arrives, but stripping Huawei out is damaging services badly.