Prompted by your thread, I decided to look this up.
A couple of seconds before Mary appears for the first time, there is a shot of the audience, and the women in that are thus the first women to appear on Channel 4, including - assuming they are a woman, never assume, etc - this really bored-looking one.
Then the mythical Mary appears in full Richard Ayoade cosplay:
Then appears Vorderman, who "works in computers", wearing brown on brown, accompanied by an insinuation that she has a "pretty good figure". What a show.
Anyway, I watched the entire episode, and Mary is neither mentioned, heard from nor seen again. What a career. So all we have to go on is that one picture above, and her silhouette in the outro.
The Mary Craig you refer to died recently and there is very little information about her to be found, nor images. She would have been 54 at the time of the show's recording, so, well done there, that's a good 54. Her obituary in the Telegraph includes
this photo, which, when compared to the one above, definitely shows a likeness.
And if you turn a picture of her from the cover of one of her books into a silhouette and drop it on a blue background, there is a likeness there as well;
Mind you, if you turn a picture of Neil Warnock into a silhouette and drop it on a blue background, there's one there too:
So that's not really conclusive at all.
In conclusion - pass.