I've been to dinner parties where we've enjoyed some espresso fairly late at night. I don't think I've noticed any problems sleeping after it, but I typically had a few glasses of wine as well.
Do you have a time frame after which you won't have an espresso for fear of not sleeping well?
actually taggart I have found that I sleep alright even if I have just had coffee....maybe it has to do with how tired you are and the coffee intake does not alter that factor...