In message o.uk, Dave
Liquorice wrote

OK we are talking Bristish Gas
but I don't think even they are that incompetent. B-)

With BG you can give them your own meter reading on-line as many times
as you like. A monthly reading will result in accurate bills.

A shortfall of £700 could result if they have assumed that heating is
supplied by another utility company and no meter readings, either
official or customer self read, have been applied to the account.
However, there would be no shortfall if the OP has given the equivalent
weekly DD amount rather than a more normally quoted monthly amount.
--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk