A hair colourist dubbed "the king of rainbow" has clients fly 1,600 miles to him just so he can dye their hair - and charges £500 up to a session. Mykey O’Halloran, 31, began to experiment with rainbow hair in 2012 and now brightly coloured 'rainbow' hairdos are his speciality. Mykey, who has 16 years experience in hairdressing, has rainbow hair and beard himself.