The three-hour walking tour's attractions include the original Great Hall of Hogwarts School, built for Harry Potter And The Philosopher's Stone.
Tom Felton, who played Draco Malfoy, said:
"I will never forget walking through the Great Hall for the first time. It was just as magical now as it was."
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BA said the strikes will impact "only 1 per cent of our total scheduled flights across the three days."
It's another mild day in the north and west, but cold in the south and central England.
The singer, songwriter and rhythm guitarist for the British rock'n'roll band died on Christmas Eve aged 68.