I saw a variety of Stevia-containing packs with the other sweeteners today.
some have maltodextrin as the bulk filler, but I bought one with erythritol instead as I think it is one of the Sugar alcohols at affect me the least.

Quite expensive, £3.32 for 180 servings (each 1/3 teaspoon is supposed to be = to 1 teaspoon of sugar) but the shelf label said this is their special starting price, and that it will be closer to a fiver in a short while so I bought 2 jars.

They also sell boxes of single serving packets

http://www.waitrose.com/shop/Browse...true&langId=-11