As above it's dependant on your contracted hours. Ours only allow one day at a time after that one day you're expected to use annual leave, unpaid time off etc. you have to apply using a form for it as well
Pro rata is based on your contracted hours. So in my trust it’s 5 days for full time staff. If you work 4 days then you get 4 days emergency entitlement over the year etc and our policy says in a rolling 12 months period so it starts from the first episode so if you had your first day in march then next march that would drop off. It’s always at managers discretion and it’s only ever 1 day in our trust to give you chance to work something out for other days
Pro rata means if you work full time you get the full allowance, if you work part time you'll get a relevant proportion of that. If your contract is 50% of usual hours you'll get 50% of the entitlement. I would assume it matches with the financial year, April to march