The Rabbit Hole - Vegan Hair Parlour Based in Goldhawk Road, West London. Run by vegans
Monster House London is an alternative vegan hair salon situated just off Brick Lane. Tel 020 7377 6486
Daniel Field Hair Salon Based in Barnet, North London. Daniel Field ranges of colour and hair care products have no animal bi-products and are cruelty free.
Glasshouse Salon Hackney based hair salon. They state "Our products do not use animal ingredients and are suitable for vegans and vegetarians (with the exception of one of our hair waxes which contains bee wax)
See also this article in the Metro
And this UK map of vegan friendly hair salons