They are the only ones I have found. Not sure if it would help your DS but Lakeland (and some shopping channels) sell the EasyYo yogurt making kit and you can buy low lactose plain yogurt (only seen it online, got it at Hollandand Barrett). Also, if DS officially diganosed with a food problem your drmaybe able to prescribe some specialilty food (certainly they do for gluten free items, not sure about dairy-free).
We used to buy Provamel vanilla pots(usually in the free-fre section,4 packs, in cardboard wrapper)which DS LOVED. Not perfect-ingredients wise but not bad! We actually realised (After a while) that DS couldnt tolerate soya and gave him a raw bottom

(