I compared John Frieda with Fudge purple shampoo and there was a clear winner - Liverpool Echo
Crazy Color Shampoo for Coloured Hair, 250 ml 250ml purple : Amazon.co.uk: Beauty
blonde revival™ purple toning shampoo | Aveda UK
PRO:VOKE Touch Of Silver Brightening Purple Shampoo 150 ml, Neutralises Yellow and Orange Tones, formulated With Violet and Blue Pigments : Amazon.co.uk: Beauty
Best Purple Shampoo Bar UK | Blonde & Highlights | KinKind
Best shampoos for grey and silver hair: Colour correcting formulas for light and dark hair | The Independent
Best Purple Shampoo For Blondes | POPSUGAR Beauty UK