Thanks again to everyone. Apologies it is in fact a modem/ router supplied originally by Post office. The Ethernet cable is a possibility. The only issue is that I have three Ethernet cables from the router to various close by devices at the moment . I have a sender which extends the signal to the back of the house but with limited Ethernet ports.
So are you actually a BT Broadband customer?
No supplied by Post office. Taken over by Shell now talk talk 😂
Then you need to ask on the Talk Talk user forum, as this is a BT Customer Forum.
https://community.talktalk.co.uk/
Someone there should be able to help with the connection arrangements for their router.
It will be exactly the same as for BT