I'm unable to login to the bt wifi app. It says I need to accept the terms within the bt community, which I have and still cannot log in.
You do not need to accept the terms of the BT community in order to log onto BTWifi.
Assuming you are using the free BTWifi that comes as part of a BT Broadband package, you need to use the BT Broadband account holders BTID username and password.
See link