Yes I use the Sainbury plain GTY one most of the time too but when I get the chance I buy the Asda smartprice, it's only got 0.1 % fat and tastes not much different: ASDA Smartprice Natural Low Fat Cottage Cheese (250g)
Not sure about flavoured ones, I would think pineapple is out of the question and the onion & chive one you'll need to double-check the list of ingredients. I add my own chives, my garden is full of them