Energy bill query

Aveline all my comments are based on supposition because I don't know your situation, but these are my thoughts:

Are you paying a set DD every month? If so then EDF have probably looked at your last 12 months usage and estimated where you are likely to be in 12 months time. So they are assuming that the price caps increase as expected and we don't get any government intervention.

No company can increase your DD unilaterally without your agreement, unless you are actually owe them money, which I don't think you do. Phone them or get online and tell them that you do not want your DD to increase at the moment until you understand better what is going to happen over the next few months.

Thanks volver. They haven't told me my DD is going to increase (yet!). It's all done online. There's no one to actually speak to. They have the record of our previous usage over the same time. I can only assume that energy companies routinely overestimate - business is business - so I have made them a free loan of £700!
I had success via a complaint on Twitter re the mess they made of a smart meter installation and subsequent removal. If necessary I'll go that route again.