I don't know if this has already been covered. I looked, but couldn't find anything. Normally, I don't have a problem adjusting the height of an object on a wall (lights, paintings, etc...), but so...
So having done some more research I can confirm that there is a slightly awkward workaround - bb.moveobjects, hold ctrl and press 9 to bring objects upwards, press 0 to bring them back down.