Can anyone help with working out holiday entitlement when working term time?

[insancerre]

I need some help as my contract is as clear as mud.
I work 45 weeks a year in a pre-school that is only open 45 weeks a year. I work fulltime, 5 days a week for 37.5 hours a week
How many weeks pay am I entitled to?
What would my holiday entitlement be if 28 days is the norm for people who work 52 weeks a year?
I can not take any holiday during term time and my pay is salaried, i.e the same every month

The holiday is built in to the time you take off so you should actually get paid the equivalent of 50ish weeks prorata-ed over 12 months

45/52.14 * 28 days

Assuming the 28 days includes bank hols

I make that 24 days leave to be paid for

So pay - 45 weeks plus 5 weeks and 4 days
50 weeks 4 days

The preschool is def open 45 weeks? Not open school term times? (38/9 weeks) such staff are often paid for 45 weeks inc holidays

thanks,
yes the pre-school is open 45 weeks
only closed for 2 weeks at xmas, 1 at easter and 4 weeks in the summer

Sorry I meant 4 weeks and 4 days leave, can't add up tonight!