Not sure if the award is still the same but when I had the shop it was half hou UNpaid break every five hours and that was it.
We also gave them a meal if they were working the 5-9 shift when they finished or when on break.
So you are not legally requires to give them any break at all but a 10 min smoko if they have the time would keep up the morale. Smoke breaks are also UNpaid legally speaking.