I've had thermaboard put on the external walls in a couple of rooms, now need to fit new radiators. The 2 new little radiators upstairs feel pretty solid fitted with hollow wall anchors. Question is, will the 600x1000mm rad for the front room be ok on hollow wall anchors or will it trash the plasterboard? I've looked at all sorts of fixings and can't find any long enough to go through 55mm of insulation to reach the brick. Don't think cutting a window in my nice new wall for noggins is a very appealing idea either...!