UPDATE! I have something that looks like a dress!
It still needs a zip (and the rest of the back seam sewing), a waistband facing and a a couple of hems (dress and lining) but it's very nearly there!
I am undecided whether the waistband needs embellishment. I prefer it in theory with the extra lace, but I think it might suit me better without!
I need to get my bridesmaid back for another try on!
I also probably need to add more tulle to my petticoat, as the weight of the lace means it is just a teeny bit too long, but that might sort itself once I've got the horsehair braid hem in place.