Fitting window regulator

[Greeny.]

Hi, just trying to fit my replacement regulator which all seems simple enough but I cannot get it into place! Really annoying, as I can get the bottom half in fine but when I try and swing the top half round into place it hits on the bottom of the window! Ive tried putting it in the other way round but then I cant get the bottom half in the door at all!

What am I missing here?

 

[Greeny.]

Fixed! Thanks for the help.