I have just changed a radiator which had a sheered bleed valve. I measured it as a 1200 mm radiator but after fitting the new one to the wall (different brackets from old one!!) I have found that the valves (unchanged) are actually only 1170 mm apart and if you force them apart to meet the new radiator they are not square to the ends of the radiator inlet/outlet pipes. Any suggestions as to how I might fix this?