I thought it was possible to assign a material to a face in edit mode, different to the material assigned to the rest of the object. I can’t seem to do it though. Whenever I select a material it is assigned to the whole object in edit mode, even though I have only one face selected. Must be doing something wrong but I can’t work out what. I did solve the problem by separating the face as a separate object, assigning the second material, and then joining the objects back together again. Seems a bit of unnecessary work though.