I wish I could find the article with an associated photo, but anyway, during location recording of "The Pyramids of Mars", Tom greated some children...in a mummy costume! For years I just assumed the Doctor supposedly disguised as a "Servicer Robot" was simply one of the other performers and Tom dubbed his lines later. (He may have done so anyway as his voice is not the least bit muffled.) But the article showed Tom sitting in the "strong-man" proportioned wrappings sans the headpiece with nearly a dozen kids flocked around him. It just seems funny Tom would have gone to the trouble of wearing the costume. I don't recall those shots presenting body language that let us know it was Tom inside. Still, that shows dedication to one's craft.
Tom also stated in a few interviews that while he was a smoker, he made the effort not to "light up" while in costume as he didn't want to present that kind of image to the children.
Sincerely,
Bill