Like many people working with a Contract for Services, your holiday is calculated on the number of hours you work each week.
The calculation is quite complex but we want to ensure you get your full Holiday Pay entitlement.
The Governement website https://www.gov.uk/calculate-your-holiday-entitlement/y/casual-or-irregular-hours helps, but under estimates your 30 day entitlement.
This website, just like the Government Website explains the first calculation, but there are still further calculations which are important to ensure you get your Holiday Pay Entitlement.
The basics are better explained by ACAS. http://www.acas.org.uk/media/pdf/5/h/Acas-guide-Holidays-and-holiday-pay.pdf
In the next few weeks we will add further pages to enable to you to check your entitlement week by week.
but in the meantime please ask if you have any concerns.