Prince Harry hasn't washed his hair for two years.
I don't know, is it just me or is there a slight disparity there?
Not really.
First of all, Harry, when he's not deployed, probably sees a barber on a two-weekly, if not weekly basis - both his military service in the Blues and Royals, and his official role, require him to be well groomed, and except when he's out on the town socialising with friends, he is generally well turned out. Even if he truly doesn't wash his hair himself, the barber will be doing something to deal with any issues. Secondly, this is a report that originally came from The Daily Mirror, a sensationalist tabloid - I wouldn't necessarily assume anything they print about the Royal family is true and accurate. Thirdly, Harry is still a rather young man, though he has matured a lot over the last couple of years, and while he has occasionally made some very unwise decisions those were down to lack of maturity, not lack of intellect.