OP, what is it that you actually WANT out of a job? Is it to earn money, or to keep you busy, to use your brain, to give back? I think once you've established this you might be able to focus on specifics a bit more.
Would you consider voluntary work? Loads of charities would welcome extra help, and this is more likely to be available on your terms time-wise.
If you want something paid, it's more likely to be a case of either starting your own business (which I doubt will give you the work life balance you are looking for) or adjusting your expectation in terms of salary/job level (in terms of using your brain).
I am incredibly lucky and work in a school, in a somewhat watered down version of my pre-kids career, but still something that allows me to use my brain and feel like I'm contributing to the place as a whole. I work 3 days per week, year round, although there may be scope to balance my hours more towards term time once DD starts school.
In my team there are a few term time workers, although most do work full days (8-4 ish). A couple of roles fit round term time only - we sometimes design these specially to attract more experienced/higher level workers who are willing to downsize their salary expectation significantly to get a job that fits so neatly into their lifestyle. I work in an office in an independent school, rather than on the teaching side.
If this is the sort of thing you are willing to consider, I would suggest a few things:
- Volunteer in a school. Get experience so you will be well placed for any paid roles that come up.
- Think carefully about what hours you would be prepared to work, both within and out of school hours, and the level of 'extra' you could commit to (don't forget INSET days, nightmare for childcare as most school staff need to work them!)
- Keep an eye on Greensheets (schoolvacancies.co.uk) as this is a great hunting ground for jobs, and will give you an idea of what might be available.
- Be patient. If you are prepared to wait, you never know what might turn up.
I do think you sound like you want it all, but why the heck shouldn't you? I suspect we all do really, and it's a case of deciding how much you can/want to compromise as inevitably this will have to happen to some extent. Best of luck with finding something that suits.