According to Andy on his website "It’s not great but I’ve got to deal with it, don’t think I will be doing it again anytime soon! My hair grows real fast, by Miami it will be a decent length.”
... "real fast" ... he's spending too much time in the States!
Here was me thinking Andy had decided that if you can't beat the Undertaker in (grand slams) then you might as well join him (as far as the hair goes), but apparently someone on MTF had that idea first ...
Yep, j'torian. He is the one who put up a hilarious thread on there, showing Davydenko as he would look with varying hairstyles of other players. He is obviously a very accomplished photoshopper - I think I would never quite believe in a photo published by him. . .