Hi,
Thank you so much, I would have never thought of that!!!!!. Converted several Bump texture materials that I was having issues with from greyscale to RGB - all working a treat. I wished I'd tried posting here sooner...I was so totally p**d off that I bought substance painter on steam - OMG! the totally janky way to add stickers/logo's to say e.g. graffiti to a brick wall whereas in 3DC it couldn't be simpler - assuming your brick bump maps are in RGB, that is ;-)