You may be looking for I Was a Monster!!!, the short story.

I Was a Doctor Who Monster! was a 1996 semi-professional documentary released by Reeltime Pictures, and developed from an idea by its presenter, Sylvester McCoy. Various groups of creature performers were reunited around the time of the Paul McGann telemovie and asked to recall their memories of what it was like to play the various creatures in Doctor Who. Performers were drawn from all major eras of the programme's existence to give a wide view of the craft of creature performance. I Was a Doctor Who Monster! was notable for being one of the few primary sources of information about many of the interviewed performers.