Buying was was focused on July 2051 bond, with about two thirds of the buying there.
That £1 billion has gone a long ways. At the peak of covid-QE, the Fed waw buying $300B per day.
You can look at that two ways: 1) They didn't do much or 2) There wasn't as much forced selling as feared
Of course, the massive long end rally today would have made people a lot more reluctant to let go of the bonds.