The answer can be found on this very website. Betty worked in the lunch room of a drama school that Graham Norton attended. For more info, see also "interview with Betty" on the DVD "The Best of So Graham Norton."
I saw the one-sentence bit in the trivia you refer to and that was it.
Aside from the fact that she was a lunchroom employee it doesn't explain WHY she features so prominantly on his show. I'm waiting for the series to come to my local video rental place so I can check out the episode you suggest.
Until then, however, and for the benefit of those of us who just want the question answered, just who is Betty Hoskins, and why does this otherwise blameless lunchroom worker figure so much on Graham Norton's show?
"If you don't know the answer -change the question."
Betty was a random contestant on his show and won a tongue-shaped dildo, which was consequentluy reffered to as "Betty's Tongue". She was invited back for more shows and the audience loved her and she became a staple of the show. For which I am deeply grateful as she has brought much hilarity to my life.
E.g when she said "I'm a bisexual virgin" in imitation of Adele from BB and Dustin Hoffman did Johnny HAHAHAHAHAHA fantastic accent! And who remembers "Hunt Betty!"?