hmmm, if you want to avoid sweeteners, I'd stay away from Isey Skyr yoghurt - see ingredients list below:
Ingredients:
Skim Milk, Water, Modified Maize Starch, Flavour, Thickener (Pectin), Vanilla Pods Extracted, Sweeteners (Sucralose, Acesulfame K), Colour (Beta-Carotene), Skyr Cultures