Well, my night out was absolutely bloody BRILLIANT!! Thank you so much for your wonderful advice.
We went to an immensley posh hotel where we took a gondola to a restaurant where we had vodka apperatifes on a hanging balcony, watching fish flit through the water and enjoying a light show from another nearby hotel. We ate a fabulous 5 course meal. Then we took another gondola to a buzzy bar and drank more vodka. Hooray! I laughed so much I was wheezing. We told terribly rude jokes in the posh restaurant. My friends said my dress was fabulous and that I looked skinny (disclaimer: I am not skinny, but my friends are very sweet). It was great.
Dh didn't have too painful a time with the children either - they were a bit grumpy, but no screaming or hysteria which means I can go out again!