Tiling behind a grid isolation switch panel

[tumblewood]

Advice please.
I have a wall I wish to tile that has a square 8 gang grid isolation switch panel.
The tiles are about 8mm thick and wish then to go under the front plate.
Hench I need the front pate further forward, together with the switches.
Behind the front plate are two grid panels on top of each other each carrying 4 switches which are in turn fixed by 2 - m3.5 screws to the back box in the wall
How do are bring forward the switch grid panels.
If I loosen the m3.5 screws the grid panels become loose and floppy.
It is crying out for some kind of packing or is it a matter of bringing the whole back box in the wall forward by 8mm or so.

 

[Dave]

Use normal longer socket screws like you would with a normal face plate on the wired plates, Then the cover plate still goes back on as normal.