Genuine Land Rover Driving lights - how to open them?

I have a pair of 6.5" Land Rover badged driving lights on my Land Rover bull bar. The lights are made by zkw (I think) model e12 (1995). I cannot figure out how to open the plastic casing up? No screws, (not even a screw behind the Land Rover badge) Has anyone any ideas? I tried flexing the two case halves apart with a large screwdriver but cracked one.

If there same as mine(with the LR badge at the top and plastic silver guards) then there are three recessed screws on the rear..

Thank you for that helpful advice. I origionally thought they were holes for rusted blind rivets and ignored them, but on closer look they were rusty screws after all. I manged to get the rusty screws out.
I had hoped I could open up the reflector and clean the inside of the glass/plastic (as its gone all milky) but it looks like I cannot.