If you do long hour shifts you’re better off because the holiday £ is paid every hour you’ve worked where as the ‘‘regular’’ holiday is fixed so in theory you might end up making more money. Also imo better to get paid on the spot when it comes to agencies, the sooner the better. You don’t want to find out 2 days before Christmas that oh btw their holiday year runs Jan-Dec and you have 7 days left in the year to use up your 12 says accrued hols like has happened to me before
Or they go out of business or some such eventuality