That's weird! A tray siliconed against tiles is not a good job. That drawing doesn't make sense.
What I do agree with is it states the doors will not fit if tray is too far tiled over, but surely doors for shower trays should not be so big so that all the shower tray width is needed?
this realy annoys me ive done a few jobs at a house and when i went there today theyve had a new boiler fitted actually its not so much fitted as slung on the wall
View attachment 17865this realy annoys me ive done a few jobs at a house and when i went there today theyve had a new boiler fitted actually its not so much fitted as slung on the wall