I've heard Claire mentioned that her colour is a home colour - she has mentioned the shade and make before (sorry,can't remember!!).I also heard AY confirm this on a PK show the other night.
I know CS has said previously that sometimes she goes for a few strands of highlights at her hairdressers every now and then (not sure how that works with home colour??...I home colour...and couldn't fit that into my regime!!) and also that she uses heated rollers.