DD's Dad insisted on buying her a complete set of school uniform himself at the beginning of term (gave me loads of grief about it as he insisted on being at her uniform fitting etc), despite us having a written agreement that I buy all the essentials she needs as he pays CM via the CSA. DD changes homes through school, so is always wearing uniform when she arrives at the other house anyway, so doesn't need more than one set of uniform and a few spares 
Anyway, the last two times she has arrived here, she has not been wearing the same clothes that she left in the previous week, but has been wearing clothes he bought her.
Not a problem, and normally it wouldn't bother me, other than the fact that he has bought her 100% polyester school trousers, which I would prefer to avoid as she is prone to cystitis and so I try and make sure that she wears breathable fabrics as much as possible - certainly when she is wearing them all day.
We now have two pairs of polyester trousers at our house that he has bought, and he has two pairs of cotton trousers that I have bought - which will undoubtedly stay in the wardrobe at his house until she has grown out of them. Should I make an issue of it and try and get them back so she can wear a pair when she is here, or shall I just go and buy more cotton trousers for her to wear and keep the poly ones here? Whichever I do, it will end up in more grief for me - so I'm wondering whether to just stick her in the polyester ones and hope she doesn't get another infection 