You often work more as managers miscalculate the rota, first cutting staff then it's always busy so they ask oeople to stay longer. Managers even cut hours below the 35 contracted hours and justify this with dome written rules I never knew about. My hours were cut to zero over the Christmas period where I was forced to look for another shop. Lots of favouritism going on,if the manager doesn't like you he/she gives you either less hours that you don't have much money, or they overwork and exhaust you that you don't have a private life.
You can choose to take any extra hours you want, it is not forced upon you.
I do 24 hours a week.when busy they ask you to stay.
I Have full time contract (35 hours), but I usually work 40-45, which is good.
I have 35hrs contract,but I always work over my contract.