The contracted hours would be 41.25hr per week, but we work on an annualised hours basis - which means at certain periods you will be required to work more than this - and at other times you will be required to work less. 
On average you will get 2 days off a week over the year - there is no set rota - but you will know what you are required to work around 6 weeks in advance. There will be long days and evening (9pm) finishes during the summer - throughout the residential season and during our winter we are open until 10pm - but these will be shorter shifts 1-10pm-ish. 
We rarely require staff to stay over with the exceptions of supervising Duke of Edinburgh Expeditions.