Thank you for your prompt reply Snacks! I do have some PUL covers (haven't used them yet!) Do you have to change the cover every time you change the nappy? I guess the answer is only if it is wet/soiled? Also, my aunt knitted a cover from wool, but I don't know what "lanolised" means - is that a treatment you can buy from the supermarket or is it an intrinsic property of wool?