I got an email from Octopus yesterday, my fixed rate is ending next month and they gave me 3 options:
To go on a 12 month fixed rate and pay an extra £100 approx per month.
To do nothing and they would move me onto a variable tariff and my DD would be the same as what I actually used last month (extra £10 per month).
Or to choose their loyalty 12 month fixed tariff at an extra £60 approx per month.
I'm choosing to go on the variable rate as Martin Lewis advises against signing up to fixed deals at present, and I want to pay for what I actually use rather than let credit build up. I already have over £400 in credit sitting in my account, that's after asking for and having £300 refunded in Nov.
Just because they want you to pay £x for a DD that doesn't mean it's what you will use. Look at what you used in Dec then set a DD according to that with maybe an additional £20 or whatever is manageable on it.
Check if you have credit on your account that you can use to offset any increases. I get an email every month to tell me my DD will be taken on x date and when I scroll down it tells me how much credit I have.
Look at ways of reducing your energy consumption too. They send out emails weekly with energy saving ideas on if you signed up to their 12 week energy saving initiative.