Faulty terminal clamp on DC to DC Charger

I’ve acquired a 12v to 12v 30A charger for my campervan. It is second hand. It arrived with one of the terminal clamps faulty. The screw doesn’t affect the tightness of the clamp.
I want to investigate whether it can easily fixed. The heatsink and top cover are held together with 4 screws, however can someone help with getting the cover off the heatsink. Do I need a special tool or will they part company with a bit of persuasion?

Thanks very much