Need a new shower door

[Zeepster]

Boring I know but does anyone here have any experience with shower doors? The one I currently have came with the flat that I bought new about 7 years ago. It's not very good quality and the water collects at the bottom underneath the frame that I can't get to so it just goes moldy and horrible. There's too many edges and gaps where water will collect.
I'm thinking of replacing the door with a better one but not quite sure which type I should get. I've measured the width of the shower door which is 1150mm from the edge of the frame to the other edge. I've noticed that most frames come in 1000 and 1200mm sizes? Is that the door size or the overall size from edge of the frame? Am I able to cut the frame to size?

Cheers

Colin