CAT away, before or after plunge
I'm not organised AT ALL. We have basic materials in the house (paint, coloured paper, pens, scissors, glue, food dye, corn flour, dressing up box, internet access, lots of story books) but I absolutely do not plan our days. So I can find myself reading with a child at almost midnight thinking "oh, I guess that's us doing literacy, then", or I can find myself at the zoo having a long involved conversation about whether or not baby snakes are called worms, and realise "Ah! A Biology moment!"
I do try, with each child, to have a concentrated half hour every day when we are completely on their agenda, whether that involves playing or cooking or talking or reading or writing or anything else, and sometimes we manage much more time than that, but concentrated 1-1 is sooooo efficient educationally that I reckon half an hour as a minimum is probably enough educational input per day (oh, and I am the parent who full time works. God knows what they all get up to when I am out of the house...)
If your children are wanting lots of things which are clearly "educational" (tis a bit like jumping off a cliff coming out of school after many years of people telling you that playing and learning are different things) then how about setting yourselves up so that at least twice or three times a week you have educational commitments or "field trips". i.e. Thursdays are biology, so you either go to the zoo or to oh-what's-that-water-bird-reservoir-called-that-flamingobingo-likes?, or, WEdnesdays are science, so maybe a trip to @Bristol, or you could join the national trust and do lots of history trips to houses and gardens and talk about how people lived in the past. And if your children want to draw or write things relating to it then yay, but if not, shrug.
In your wobblation, I would STRONGLY suggest getting yourself down to Felix Road Adventure Playground in Bristol next friday, 11am onwards (I know a woman who goes from Chippenham - it takes her about 30 mins in the car, otherwise, train to temple meads, train to Stapleton Road and it's ten mins walk if you have a good map . there are lots of children there the same age as your children - it might really reassure you.