I too am surprised you let the balance build that high without noticing. The thing is that’s a credit balance upon which they will be paying you interest. Think of it as a savings account rather than a cost to you. Just ask for it back if you want it. People do need to be proactive with their...
If you ring them they will always change it. My Ovo bill has regularly forecast I will end the year with a debit because we had 5 adults in the house last winter. As you say it is based on previous year usage. That’s an entirely reasonable starting point. I just ring every 3 months when they say...