Right just kicked it up and bled the rads, the one in the bathroom was blowing air for at least 4-5 mins without a drop of water coming through, i take it this wasnt right

The one in my bedroom doesnt have a bleed screw for some reason although it gets fairly hot so shouldnt be a prob, pressure dropped from over a bar to just under a bar after i finished bleeding, i take it thats ok? how long should i give it to sort it self out?