I think people have linked to some really nice dresses, and some that I really dislike. I had a little read of the article someone linked to and it seems to me that there is such a variety in how people interpret the dress code. So whilst a maxi floral length dress might not be the sharp cocktail look some people think is appropriate, it is unlikely to be a glaring error.
It is also tricky because I know what the bridesmaids are wearing, and so many of the dresses I like would look like I was trying to be part of the bridal party!
I think I will probably wear my dress because I love it so much and I felt beautiful in it.
However, I have also spotted this one which I quite like... www.vinted.co.uk/items/6337482968-classy-scarlett-and-jo?referrer=catalog