from my knowledge(10yrs in cafes and hotels) after 5 hours a break is needed(1/2 hour unpaid) a ten minute break after i think it is 2 or 3 hours. i know it is busy but it has to be done as you can get in trouble for not 'allowing' breaks.
if any are smokers i believe there smoke breaks are the paid breaks.
you may be able to work out a deal with them( although not sure on the legality side of it) that they can tack on the extra 10 minutes on the end if the were unable to get a break in their shift.. Hospitality is all about flexibilty for staff and employers..