I have taken mine off to clean it.
As I remember, you just need to undo the 4x cross head screws on the side near the strap lugs, and lever it off with a flat bladed screwdriver.
It will clip back on as a push fit, ready for the screws to go back in.
If it resists going back on - place the plastic bezel in very warm water to soften it up.
Don't mess about, if you bite the bullit and crack on with the job it's easy.