Everyone, thanks again for all your advice.
I ordered the modem router and it arrived today. I set it up and everything went according to the instructions.
Sadly that's where the good times ended.
The connection to the internet drops regularly - I get ten minutes at most before the revolving circles of time advertise the information super highway has turned left at the traffic lights. WiFi is also terrible. I have not had chance to see if it extends further than the Bthub as the passwords are rejected, rejected, rejected, then accepted, then rejected...and the connection to my Oculus Quest2 flits between the 2.4 and 5KHz bands seemingly at random for its own amusement.
Trying to watch you tube for example and I get a minute of video followed by a few seconds black screen and then the video picks up where it left off. This repeats until I get bored.
I'm reasonably intelligent and have played with computers for forty years, but this is driving me crackers. I've put the BT hub back on and things are as they were ie working much better than the tp- link, but I'm still feeling I should be getting better wifi/internet than I am.
Do you think I simply have a faulty tp-link router or am I expecting to much?
Andy