Replacement lids for cups

[singlewiththree]

I have some nuby cups from tesco which the children have chewed all the lids and also some First years cups which again have chewed lids and the lids tend to fit both style of cups. Does anyone know if you can get replacement parts for these?

http://www.buyersguide.com/SippyCup/TheFirstYearsDisneyPrincessesSippyCup.php