In the March 28, 2006 issue of The Times Paul Hoggart wrote an article about the filming of The Chatterley Affair and his father's part in the trial. His father was Richard Hoggart, who testified in the obscenity trial about the book, when he was Senior Lecturer in English at the University of Leicester.
"I might have stepped out of the TARDIS. Arriving at a disused law court in Kingston, southwest London I came face to face with Doctor Who - dressed as my Dad! My Dad in 1960. When he I was 8! The Doctor (aka David Tennant) was in a small crowd of actors playing lawyers and members of the public, all in perfectly reproduced 1950's attire. Using archive videos, he had been practising my father's accent and intonition, and captured them rather well. He was wearing long Teddy-boy sideburns (part of his Doctor Who getup), which my father never had. Even so, it was all rather spooky."
David was only filming that day and then he had to go strait back to filming Doctor Who in Wales so if he had shaved his sideburns he would not have had time for them to grow back!