Petticoat for girls

[bookwormbeagle]

My DD, aged 6, has had some beautiful floaty summer dresses handed down to her from a relative. Really lovely, fit nicely, until I noticed the cotton material is a bit on the sheer side and they're ever so slightly seethough!

Hence the search for a basic white petticoat - having no luck in tracking one down. Lots of frilly lacy layered numbers on eBay, etsy and the like, but nothing plain.

I thought for sure M&S would do them, but sadly not. Any ideas oh wise MNers?

Tia