In reply to all:
Thanks all for your input so far.
Sorry, yes, to answer a few questions I should have addressed initially ...
1) The connection fails and says "There's a problem with your connection. Let's try to fix it." The Xbox then suggests four courses of action:
Suggestion 1 is to disconnect and set up again. I have done this and have restored network settings to factory settings as per one the only google help I found (https://community.ee.co.uk/t5/Gaming/Connecting-my-Xbox-to-EE-mobile-broadb...). A different network and router but same issue. Didn't work for me.
Suggestion 2 is to power down the router and try again. Which I've tried.
Suggestion 3 is an incorrect password. I've been super careful and tried five or six times. I've also tried the WPS password on the router.
Suggestion 4 is online help page which no longer exists.
2) I've tried manually inputting IP and other network settings. No luck
3) I've tried ethernet wired connection. All works fine.
4) Yes, all other devices seem to connect fine. I've got a 2010 macbook, an iPhone 8, three TP-Link smart plugs and two TP-Link Kasa Cam cameras on the network. According to the Huawei manufacturers specs I should be able to connect 32 devices. So there is plenty of space.
I'm at a loss really. I'm not particularly tech savvy!
Post edited at 10:31