Re: Can someone explain please?
As a result, HM Money-Bags will immediately give that money back to Openreach to install broadband
Not quite. BT will refund the money to the councils. It's then up to the councils what they do with it.
It's like you paying Amazon £10 for a book with the promise by Amazon that if it proves popular they will drop the price and refund you. A year later the book has turned out to be more popular than Amazon expected so they credit your account with £5. What you do with that £5 is up to you.
Councils can pay BT for more coverage. Or they can pay someone else for more coverage. Or they can buy some pretty flowers for the park. Or they can pay for a
jollyfact finding trip to the Bahamas. Or they can put the money in their savings account.