Plasterboard (Podsmead GL1)

Does anyone have any large offcuts of plasterboard please? It's for the inside of built-in wardrobes in the old prefab bungalow I'm renovating for relatives. There are two cupboards side by side, but in different rooms that are in the wall. It's literally made of old very thin particle board, thinner than most cardboard boxes! I'd like to add a basic wood batten frame and line with plasterboard so they can withstand the occasional accidental wheelchair bump, and so it can be painted and feel clean and new.
Please and thank you