i think you will find that the ban covers 'smoking in the workplace' which include any property of the business, car park included. i work for royal mail and at the moment the site has designated smoke areas, as from july (unsure) the whole site wil become a designated smoke free zone.
not entirley sure what the legal standing is, but i believe it becomes the employes responsibility to protect the non smokers, so a blanket ban is the way this is being introduced
so, a no smoking site does not need a smoke break, and unless the break is written in your contracts it is classed as gratis and can be withdrawn at anytime