I have an uptodate box etc to BT, but currently have the basic entertainment package at a cost of £16 pcm. Could I get rid of the Entertainment channel and just use Freeview FREE?
It depends , AFAIK, if the box was supplied after a particular date , it remains BT property, so if you cease the BTTV service you have to return the box , if the box was supplied before that date , it’s yours to keep even if you stop subscribing to BTTV , so it probably depends on when the box was supplied.
The date in question is the 13th December 2019. So if you had the box prior to that date it's yours to keep , regardless of what Customer Services might tell you.