I've a not dissimilar problem. Or, rather, the inverse of the situation.
There are two dark lines going down my 17" MBP's panel, that go away once I increase the backlight brightness.
It's only annoying if I turn down the LCD backlighting below ~60%. At times I'd like the display darker but then I see the lines and spaz, so I put the lighting back to normal and whip out some sunglasses. 😀
But I only see it on predominantly white screens, and usually I've got programs and web pages up so it's shrouded and not annoying.
If I turn the brightness up to a certain point, it goes away and the whole display looks even.
I don't have LCD backlight bleeding, however. That definitely IS abnormal for a MBP.
Looks normal to me. Taking photos of a black screen in the dark will usually end up like that.
Do you have any problems during actual use, i.e. do you see bright/dark areas when you watch videos or so? If it is notable during normal use, take it to apple and have them fix the screen.
It's good to view it in dark situations as it shows off the largest range of bleeding and differentiation between brightness.
You don't pay in the vicinity of £2000 for a machine that the top half of your image is going to be darker on YOUR machine, it could (and chances are will) lead you to make changes in projects (specifically video editing and photography) that you wouldn't normally because your screen is defective.
then get it replaced. if you notice something and it hinders your vision/work on projects what are you waiting for? i just cant tell by the pictures is all i was saying, but yes, if i noticed my screen was f'ed up id be the first in line for a new one