I haven’t done a colour correction in years and need some advice. My client has wella kp 55/0 every few months and has done for years. She is about 25% grey natural level 5 and would like to be able to go lighter to around a level 7/8 so that the grey is less noticeable when the roots start to appear. Am I best off with a colour stripper, bleach bath or do I really have to go in with highlights? Any advice would be greatly appreciated x