Hmm. Still not working fully. I can get the DoorLeaf extrusions to change to Plastic, Opaque White in the top-level Ext Door Pennant dble half glazed UPVC family but when I load it into the project I am using it in it comes in with the DoorLeaf extrusions still grey.
Edit DoorLeaf JMP sub-family
Extrusions set to Material = Plastic, Opaque White
Other / Shared selected
Load into Ext Door Pennant dbl half glazed UPVC family (looks good) (also project for good measure)
Load Ext Door Pennant dbl half glazed UPVC into project
Select Ext Door Pennant dbl half glazed UPVC
Edit Type to check all Materials and Finishes are set to Plastic, Opaque White
OK
... DoorLeaf extrusions still grey.
I can see that in the door's properties, when it is selected in the project, include materials (Frame material and Finish) either not chosen or still set to Alu. These do not show in the Family Types schedule when I edit the Ext Door Pennant dbl half glazed UPVC so I don't understand where they are coming from.