I have just gone over my allowance and received two emails in quick succession.
Dear **** You're approaching your product's broadband peak-time usage allowance of 10GB for this month. We've sent you this email to help you manage your usage, and ensure you don't face unexpected charges. There's no limit on how much you can use, but once you've used your 10GB allowance, additional usage is charged at £1 per GB, provided in 2GB blocks.
Dear ***** Account username: ***** At the moment your account allows for 10GB of peak-time usage per month. You've probably noticed that your broadband speeds are slower than usual, this is because you've gone over your monthly usage allowance. Don't worry, your speed will be back to normal at the end of your billing month. If you'd like to return to full speed now, you'll need to increase your usage allowance. There are two ways to do this, you can either: - Increase your usage allowance - (73p per GB added) - Use what you like now and pay for it at the end of the month - (98p per GB used)