Hi nelle :wave: Thought i'd better help you out! Hope you are coping ok in the heat love. Not long now!

LM- Definately interchangeable. I have various fitteds and covers which i swap around all the time. Just be careful with the covers you sometimes find in BigW etc. Some are PUL, but others are PVC, which doesn't breathe which is not so good. But someone had an idea about cutting part of a BIGW nappy cover off to make it more breathable....... hmmmmm but not really sure what that was all about.......sorry! Maybe Nelle will know.