I created this at the little tabs had broken off mine, and i thought this might be useful for someone else.
I have included two files, one is the model itself, the other is a template for the tabs so you can line it up and make adjustments without having to print the whole item.

First time creating a thing from scratch, hope it helps someone. OBJ file included in the zip

Size 155.5mm x 155.5mm x 10mm
Slats are 45degree angle with a lip at the back, so check the orientation if you copy it