Should I go back to work 4 days?

Your pros far outweigh the cons. Go back to work. I always worked part time and I did horrendous hours until my elders was 2. He doesn't remember any of it. But I feel so lucky to have spend loads of time with my kids which my husband missed out on

I do 4 days a week (not a teacher). It's the best of both worlds.

It s not a big deal. You will be there with them more than not.
They wont notice the extra day.
What about their dad? Is he feeling guilty for working?

Honestly while they small they wont notice or mind so long as they have good care.
You there from 3 30.
Do what works for you.

Definitely go back to work. I worked from when my two were small, (until they were adults) . I'm so glad l did, it was good for the children too. I didn't get much income from doing it while paying their nursery fees etc but in the long run it was great and l enjoyed it

4 days term time only sounds like a good option.

Are you still with your daughters father and if so, how many days a week does he work ?

I see he is keen for the girls to be home more, so perhaps he could go to 4 days as well and have them more.

If you are separated then this might affect your child support.

My only advice as an ex teacher is that if you are planning on leaving work at 330 then you will struggle to get everything done that four days a week will need and will end up doing more work on your day off . I left as I found I was prioritising leaving as soon as I could to get home to the kids and it meant I wasn't doing enough at work and made work more stressful as I was clock watching and getting behind and trying to work in the evenings and weekends when I was tired and wanting to be with the babies . I'd be tempted to do three days when you really focus on work for those three days and then can switch off (a bit!) on the other two days .