The BBC News Centre is in New Broadcasting House, London. Not Salford.
That is why many interviews take place there.
The BBC wasn't moved lock stock and barrel to Manchester, most of it is still in London. The BBC has always had regional centres, and have been in Manchester (Salford) for a century.
There were several reasons for expanding in Manchester, but attracting more Z list celebrities wasn't one of them. Wages, costs, and rents are cheaper outside of the capital, so the huge cost of the move of some departments will eventually save the Corporation money.
It should be remembered, it is the British Broadcasting Company, not the London Broadcasting Company.
But please carry on with your misinformed, ignorant twaddle.