I've always used a childminder from going back to work after maternity leave, it was much cheaper than a nursery and I know the lady really well anyway and then when they were 3 they went to the nursery attached to the local primary school for some sessions where they will stay until 11.
My contract with the childminder is term time only and she does wraparound for the nursery days and 1 full day and for my older one, school wraparound.
It works well as the childminder does do holidays "by arrangement" and so you aren't contractually obliged
We both use our annual leave over the holidays and tend to have one week at Easter, one week in the summer and afew days at Christmas where we overlap and then the childminder bridges the gaps. She sends a list out every year of the holiday weeks/ days she is working and we just work round it.
I work 30 hours over 4 days and my partner works his compressed hours over 4 days too so we only have 3 days a week to cover.
There's also holiday clubs you can book at either the school or sports/ drama/ music/ farm park holiday clubs.
Childcare is expensive we use the government tax free scheme and save 20% but even so it's a lot and if we had to do this 5 days a week for 2 it would be a massive expense.
I'd be looking to get a local childminder to help you out, mine is a godsend. I wouldn't bother changing nurseries If they are happy in there as they'll leave when they are 4 anyway but a childminder is more flexible with wraparound etc.....
some schools also have breakfast/ after school clubs too but I have friends who use these and you can only book a term at a time at our school and they go online to book then find there's no availability for the days they want/need whereas if you have an agreement with a childminder It's for particular days