Handles and trickle vents are just screwed on and can be swapped around right now. The face drain slot that will be inside after the swap around can be cloaked over with a bit of pvc trim available from places like eurocell, fill the threshold slots with white silicone, pump them full. Drill new slots straight down like I've shown in this pic.........
The black arrows show your existing drainage set up, that is called 'face drainage, fill all this up with silicone. Drill new slots straight up and down while the doors are out, shown in green, this is called 'concealed drainage' as you can't see the exit holes, much better and tidyier
The black arrows show your existing drainage set up, that is called 'face drainage, fill all this up with silicone. Drill new slots straight up and down while the doors are out, shown in green, this is called 'concealed drainage' as you can't see the exit holes, much better and tidyier