twinkle
I second Stu's point. If we're shopping at Co-op we're supporting a place that sells meat, and the products they sell which are not own brand may also be tested on animals. (I *do* shop at the Co-op, and other supermarkets, although I don't like some of the things they sell. It's a choice between burn out or compromise). The fact that this company tests on animals is bad, the fact they make a product that is vegan is good. Where you draw the line is up to you.
I say carry on buying Original Source, but write a letter to the parent company saying that is the only product you'll buy, when they start getting more of their stuff certified by the Vegan Society you'll buy that as well :)