Franklins on Lordship Lane sell products from the WAG Bakery, not exactly a cafe (they have some tables and chairs outside) but defintely worth popping into to pick up one of the delicious chocolate tarts! I am not sure if the products are vegan though... I would highly recommend visiting the actual bakery in Brixton Market if you are in the area (http://www.wagfreefood.com/). They sell an amazing range of wheat and gluten free food including all kinds of cakes and pastries, pies and even fish and chips!