Driving in the Nineties   My mother in her nineties is barely able to move her swollen legs, and yet when it suits her she breaks a solemn promise never to drive a car again, as life is too busy for being constrained humbly by her own children’s rules. As a housewife, once, and five-time mother, something like this is a habit she is unable to forget,   having driven to the markets and tennis parties and meetings of the Red Cross over half a century. Yet there was a time, long before her wedding (in a bombed church…