Mmmm- so would this be a law firm you work for - LOL
If he is a regular in London, he will have several cab nos at his disposal for late night events- or will pre book a car!
Safe to assume I think, that he has things under control
It sounds so lovely - I really do hope that you have the most wonderful time!
Have you a wrap or something to wear over the dress for the journey there and home? I have the most beautiful hand made black velvet wrap that you would be most welcome to borrow if you wish
And shoes - what are you planning on? Something black with the slightest hint of sparkle on them would look fab with that dress????