I should probably make it clear that I do not feel that fivecandles' radical proposal of 'drop in / out' modules with a possibility of taking 6 weeks off at any point in the year is feasible in its current form.
My view, however, is that there are simpler proposals that could have equally beneficial effects - e.g. either the current holiday structure but with most weeks of the summer holidays having 'broadly educational' childcare available in school, staffed by specialists and a few school staff.
Or, slightly more racially, a shift to mainly 2 week breaks throughout the year (2 weeks October half term, 2 weeks at Christmas, 1 week Feb, 2 weeks around Easter [though not always coinciding with it], 2 weeks summer half term, and 4 weeks in the summer holidays], an equalising of the length of each term [which is why 'the 'Easter' holiday might not be at Easter], and the same 'broadly educational' childcare being provided in school premises for at least 1 week of every 2 week holiday and for at least 3 of the summer holiday weeks. Pupil premium could be used to fund a certain number of free weeks for each child from a low income family, other families would pay. Most staff would not be school staff, but a few would be, anbd those staff would have annualised contracts where their pay would be exactly what it is now but they would work fewer hours in school terms in order to be able to work for some days during the holidays. The remaining school staff would have exactly the same holiday entitlement as now, and as all state schools would work to a very similar term pattern, their holidays would largely correspond to those of their children.