I wrote a whole post similar to Sparklebox and didn’t hit post.
My hairdresser (and Kat’s and Trinny’s for that matter) has transitioned my warm brown hair to a highlighted bronde to hide the grey at the roots.
I admit I don’t pay full attention when she explains things so I can’t remember exactly why the brassy orange happens, but I think it might be sunshine, swimming, our shower water and just the colour fading. Grey hair has a different texture and is often frizzy.
I do listen to her instructions which are to use a blue shampoo and conditioner with toner. She also puts a toner through my hair to counteract the brassiness most visits.
I wonder if Kat has a bathroom full of free luxury hair products which she uses randomly, even though she needs blue or purple products, so her colour is forever quickly fading to brassy orange?