Yes, all the rads are in the main Hall.
How about doing away with all the TRVs and replace with lockshield valves; then get the system balanced. Also install an optimizing programmer, e.g Honeywell CM907 or 927, in a locked case on the wall with ventilation slots. These have six time and temperature settings each day of the week, so you should be able to program it for your usual weekly program of activities.