Sadly, I don't think there is. I know lots of people in a similar situation to yours, and many cannot afford to work (never mind doing voluntary work) because of the childcare costs. I know one person who did a PGCE refresher course (she used to be a teacher before she had children) and she received a grant, or bursary, and childcare expenses during the three month refresher, but I gather that is not your exactly your situation. Many of the mums I know get jobs as playgroup or classroom assistants once the children are in school or playgroup; it's the only way you don't lose all your earnings in childcare. I hope someone else knows something I don't know.