Ds is 2 and has his bedtime milk in one of these tommee tippee cups with a straw. The trouble is the straws are made of soft sillicone and after a few chews the cups are pretty much redundant. TT don't do replacement straws for the cups and I cannot afford to keep spending £3.99 on new cups. I would like a more robust alternative and would be interested to know what other mnetter's experiences are?