Don't let this issue stop you from working if you want or need to. It is doable, and your children are older so it will only be an issue for a while.
I use Parental Leave to boost my leave allowance. It is u paid and has to be taken in blocks of 1 or 2 weeks. I use that whenever I want a whole week off, leaving my annual leave for more flexible leave. You can take up to 4 weeks per year per child, up to the child turning 18 years, and have 18 weeks to use per child.
www.gov.uk/parental-leave
This summer I will have various combinations of my children (4 - 13 years) home for a total of 9.5 weeks. Fortunately the 4 year old has mostly solid childcare, so we are each taking 1 day per week and a grandparent is doing 1 day per week, leaving them mooching about for two days per week (non-consecutive). We work from home, but I'd be doing this anyway even if I worked on the office. I have 3.5 weeks of parental/annual leave booked to take them away (not one block) which will break things up.
When they were younger I used a childminder and holiday clubs. They're not all 10-3, though the proper "childcare" type ones that run 8-6 are a lot more expensive. Your chocked sound a bit old for those though.
As you've worked out, this is unlikely to be an issue until the Christmas holidays, when your work will expect you to ask for leave anyway. Try and take a week each; you'll both have the bank holidays together anyway. By the time Feb half term rolls around you'll be into the swing of work and you will work it out somehow.
Good luck at the interview! Don't raise this issue, as it will become much much clearer to you by the time it is really an issue.