I suspect that the boilers thermostat has stuck on high, as you have it turned down to below the minimum - which should almost turn the heating off. I guess now the boiler is more or less running constantly?
This isn't the way to deal with stuck TRV's, by the way. I'm also wondering if plumber man has opened all of the lockshield valves on the other end of the rads, maybe unbalancing the system.
John
October 2009