No grandparent help here. DH and I both take leave to cover part of the holidays, and use holiday club for the rest. It’s run at DD’s school (they also do wraparound care in term time), costs £32 a day including food (Yorkshire) and is open 8-6. It will cost us £500 for the summer holidays.
There are various activity camps around here but I’ve noticed that they are usually 9-3. I think they are more structured with a timetable for each day, from the adverts I’ve seen for them.
It’s still cheaper than nursery was (£45 a day) and the costs are holiday times only instead of all year round (I use after school club a few days a week during term time - £10 per session). I pay use childcare vouchers so I’m used to the money just coming out of my salary.
It’s usually 3-4 weeks in holiday club over the summer holidays, the October and February half terms, and one week at Easter. If we go on a family holiday in June, that would mean an extra week at holiday club over the summer, and vice versa.
We plan it all out at the start of the year in a spreadsheet. Usually we each take a weeks leave in the summer and have a week off together. For half terms, I might book the Monday off and DH books the Friday off, so we only need three days in holiday club.
As previous posters have said, you and your DH will need to keep some leave to cover inset days, the week between Xmas and New Year, early finishes at end of term, and events like sports days. I have a flexible job so can leave early for these and make up the hours later, which is a godsend.