I recently depleted the large credit balance on my account following the end of the Interest Reward scheme. Since the start of April 2024, there has been a warning on my Home page like this:

Now, I’m well aware that I can’t go on paying only £5 a month for long, but the current balance is high enough to keep me in credit into the summer. I plan to increase the monthly payment to a realistic sum before the account goes into debt.
Can anyone with experience of warnings like this and what they lead to explain ‘what happens next’? How soon can I expect to be told that I have to increase my Direct Debit? How soon after that is an increase imposed?
I’m asking because the Future Annual Consumption figure for my account is far too high, but falling. With any luck, it will meet my actual annual consumption in August or September, but until it does, the recommended DD will be too high. I’d like to pre-empt any OVO-mandated increase. If I were to adjust the DD now to the current ‘minimum payment’, my account would show an average positive balance of £150 for the next year, a figure I’m not prepared to live with.