Hi, i trust he had removed the rad leaving the two pipes sticking out with the two valves on??? If so, simply hang the rad back on it's mounts (you may need to fit these back aswell, and good luck finding the original rawl plugs, a good plasterer would have put matchsticks or screws in prior to plastering so as to identify them), then attach the valves to each end of the rad and tighten. Then simply open each valve fully and wait approx one minute then bleed the rad using the bleed valve either on the top or at the side of the rad. When water and not air comes out, tighten the valve back up then HEY PRESTO, your done.
Hope this is of some help to you????
Kind Regards
Rob. X
Rob
November 2007