As previously posted, a while ago I decided to give up the losing battle (started getting some grey hairs in my twenties, my biological father was completely silver grey by 30) and am now gloriously, happily grey at the age of 59!
I'm lucky that it's quite a "good" grey, mainly silver, but a bit darker at the back.
Love the fact that it's now lower maintenance, my hair grows very fast and the roots thing was a real pain.
Have a look at the Jerome Russell range, Morrisons stock it, they do silver, steel and platinum colours.
BTW, grey is very "in" I have noticed some young, natural blondes opting for the grey tones!