Tiling first attempt!

[Sadam]

Just tiled above bath tiles for shower use and was reasonably happy with my work. However on closer inspection the tiling is not exaclty vertically level. What i would like to know is what sort of tolerance do you have with glass shower screens. I am hoping to attach a semi-frameless glass screen that pivots at the wall. Something like below...

http://www.plumbworld.co.uk/0-15409

From what i can see the tiles are in line at the bottom and top but about a third of the way up there is a gap of about 4 mm which decreases as you go up. Will i get away with that or will i have to remove the tiles in question and pack more adhesive in???

Cheers

[tim'll fix it]

the ones I have fitted (not the model you have linked to) have a channel that fits to the wall and the screen moves in this channel.

All the shower screens I have fitted allow for a margain of tolerance. I would think 4mm is ok