‘All the best’, or maybe something like ‘Cheers’ is probably closest to the right sort of tone.
Well, it’s worth making an effort to be on time and to have the other person’s mobile number - and the number of the place you’re meeting at (if it’s a bar or restaurant), just in case you get lost or stuck in traffic.
He should also offer to walk her to her car, bus, train or whatever.
In Britain, even today, people are judged by their table manners, especially when eating out or attending formal functions.
There are certain ways you should behave and certain niceties to observe.
Again, neither of you should read anything into this social gesture.
Good manners also make a difference, of course, when you are turning someone down – even if it’s at the initial stage of a contact request.