Defender Door trim removal

2010 Defender CSW (Puma) Exterior Passenger door handle has decided to come loose. To refix it I need to remove the door trim, hopefully without too much damage. I would appreciate any advice on how to go about this. Do I need a trim removal kit? I've seen them on Machine Mart. There's what appears to be a push in stud in two corners. Do these pull out or must they be broken and replaced. I can see the inserts on the grab handle so presumably if I flick those out there will be a screw behind. What about the lock and also the door catch release handle. Does the trim just pull off over them? It's always the simplest looking jobs which cause the most problems!! Any help very welcome.