Usually door liners are held in place by clips all around the edge, and screws which hold the handle(s) in place nearer the centre of the panel. I would start by carefully easing the edges off al around and watching how the liner flexes when you pull it (gently!). Usually from this you can get an idea of where the centre screws are. The manufacturers are very crafty at hiding them away.
Lauriejb, November 2017
