New to temping here and an agency are wanting me to start an assignment later this month. They’re saying the hourly rate includes holiday pay! I know I’m entitled to holiday pay but I’m confused as to why they’re not paying my holiday separately? I’d rather I accrue it as I go so I can get a ‘pot’ when I leave but they’re saying I need to go to a third party and sign up as self-employed or something 
Why don’t they pay holiday separately?