What do you mean by fading? How big is the lawn, is it in a shady area, how long has it been in situ, do you have a dog or lots of children who run over it all the time, is it waterlogged, weedy, or showing signs of disease? What kind of maintenance regime have you carried out over the last couple of years?

Check for cockchafer grubs (sorry folks,I seem obsessed with them at the mo) see my question from 15th Oct, & Kildermorie & Bamboo's useful answers.