now that it has got really cold we have noticed that the radiator in our bedroom is not heating up at all and neither is the one is the spare bedroom - the one in my daughters room is working but its luke warm all the other radiators in the house are working fine, we have tried tapping the thermostat on the radiator but not working - have bled it and water comes out but no air - any suggestions? its really cold in there and my baby is in the same room with us so i need to get it sorted asap