High-quality kitchen cabinets were fitted to my kitchen about 12 years ago. The rear of each cabinet consists of a thin hardboard sheet that appears to fit into slots at each side and one at the bottom (just like the rear of flat-pack bookcases). How can these rear boards be removed? There isn’t enough clearance at either the top or bottom of the cabinets for the boards to be slid out so can they be removed to gain access behind the cabinets by bending them out?