Aww. you people are all so lovely! /care bear moment
I use Special effects, which is an American brand, but there is a UK website which stocks it now,
http://www.beeunique.co.uk (I think my pic is still up there in the galleries somewhere). It used to be pretty cheap to get it shipped over from the US til the dollar went down so much, so now I get it from beeunique. I do bleach mine first, so it takes most of a day to do and requires at least one helper (I usually have two - my mum and Auntie Pauline). It also knackers the condition, but I have very thick, strong hair so it can take a bit of a battering. I do use a ton of conditioner and serum tho.
I dunno how much grey I would have if I didn't dye it. Looking at my roots, I reckon a fair bit. (A friend kindly pointed out the grey on my 33rd birthday! but I knew anyway...) If I ever get too old for the red, I'll be happy to go grey gracefully so long as it's a nice elegant silver grey rather than a yucky yellowy one. You can get shampoos and stuff to keep the silver tones.