Summery bridesmaid's dress for 18-month-old?

[franch]

DD is going to be flower girl at a very hot beach wedding in the US in July. Where should we look for a dress? (Or possibly a dressmaker??) We're in London.

it is v floaty btw

Thanks both of you - CD I've CAT-ed you - very kind of you, sounds great

just dug it out of the attic, it is 12-18 months

Should be OK if it's on the big side