Interconnected

I used to love this show: Knightmare. Spellcasting: W- A- N- K- E- R (to be said in a squeaky Northern accent) [via Venusberg].

Now the question: What was that programme on Children's BBC (I think) with the red-haired girl who used to collect all the letters of the alphabet, being battled by a witch and her useless sidekick, a young boy called 'Teabag'?