Wak....You are Not arguing with me, but have drawn my attention to an oversight on my part. Bitmeter does also provide a 'read-out' of usage but, in view of what Chuck has said, I would question the accuracy of the information.
As the OP is with BT and appears unable to access its 'Broadband Usage Meter, I would suggest that he forgets about usage until BT informs him that he has used 80% of his monthly allocation; and even then ignore the fact. BT does not raise a charge for over usage on the first month one goes over the authorised limit.
http://bt.custhelp.co..._broadbandusagepolicy
Ron.