What will there be to laugh at in the new series of Sex And The City when the four friends whose youthful antics in Manhattan we followed week after week are reduced to three? Without Samantha's vivid and complicated sex life,which she handled with such careless aplomb,we're left with the serious ones—Sarah Jessica Parker (Carrie),Kristin Davis (Charlotte) and Cynthia Nixon (Miranda)—all embracing their advancing middle age. Judging by shots of SJP and Cynthia filming in New York this week,they'll be trying to convince us they are completely content with ageing—going grey while still marching through the streets of New York in vertiginous stiletto heels. I doubt Kim Cattrall would consent to grey hair as she nears 65 and,frankly,neither would I. Jenni Murray says she won't embrace the trend of growing out her grey hair like Sarah Jessica Parker who was seen filming in New York this week (pictured,left,with Cynthia Nixon) It seems to have become quite