Re: Is there an official 50th anniversary logo?
Yes. It can be seen here
Big Finish is also using that logo for the celebration.
"Eccleston was a tiger and Tennant was, well, Tigger. Smith [is] an uncoordinated housecat who pretends that he meant to do that after falling off a piece of furniture." - Lynne M. Thomas
"I'm in Hell and it's full of Avons!" - Vila