We use Grandparents and our leave to get through school holidays. dd isn't at school yet and ds's school doesn't offer OOSH before 8am or for most of the holidays, so those aren't options for us. My Mum usually looks after dd while I work normally, but then she goes away or gets sick and she looks after the other grandchildren in the holidays, so it can be a bit messy. Sometimes I look after my neices/nephews, but it's been hard as the kids were all so young and the car seat requirements meant going out with 4 kids wasn't possible. But, as they get older it is now possible which makes it a little easier to 'swap' kids in school holidays.
Working with young primary school aged kids is hard. Going to OOSH every day is tiring and limits your ability to see the classroom/talk to the teacher/meet other parents/etc.