not a cup fungus. very many of these in this area at the moment. just look like grey patches generally on bark of dead Callitris. i assumed some sort of mould until I took close-up photos, now I'm uncertain..
I think it is a lichen. Checked the area today, many specimens on both live and dead Callitris and Bursonia. Have just appeared to be patches of grey mould until recently, they now seem to be producing fruiting bodies, which makes me think that it is a lichen.