I have not yet delved into the detail of my bills for the year, to
check the numbers, but my E&G DD has been increased three times now
from £48 per month, to the present £92. My predicted consumption over
the years has been near as matters spot on and its a one year fix, due
to end in November.

My supplier has sent me a comparison, which shows the cost will be much
higher for the next year. Might they be increasing my DD, so as to
cover the cost, assuming that I will accept the much more expensive fix
beginning in November? In other words - are they stockpiling my cash,
in anticipation for next year?

It just seems so odd that they based the original DD on what my
suggested consumption was, that my actual consumption is so close to
that, yet the DD has been increased three times in the year..