Marsh said: "I thought it looked like a parking ticket but I knew I hadn't driven for a year.
"It feels extraordinary. I've had awards, like Emmys and all that sort of thing, but to have an official thing like this, I was thrilled."
The actress played three different characters in the classic Doctor Who series - as Lady Joanna in 1965's The Crusade; Sara Kingdom in The Daleks' Masterplan and Morgaine in the 1989 story Battlefield. She has also featured in several Big Finish audio dramas over the years.
Marsh co-created and starred in Upstairs Downstairs during its original run in the 1970s and reprised her character Rose Buck for recent BBC One revival of the period drama in 2010 and 2012.
She was also the first wife of third Doctor Jon Pertwee from 1955 and 1960.
(Source: Press Association)