I have been a working mother since my daughter (now 20) was about a year old. I know all about the elusive balance that I need to strike so my life does not become unmanageable. I know the particular brand of heartache that overwhelmed me when I went back to work after maternity leave, each of the four times I left an infant at home. I know, too, that the madness has stilled, a little, as the children have got older and less dependent...