maybe sometime next week
The radiators had to be disconnected and taken off the wall so that the re-plastering could take place. The re-plastering also involved the removal of the knackered and broken old skirting board. The knackered and broken old skirting board was insufficiently robust to survive the removal process in a condition which would allow it to be replaced. There was no replacement skirting board bought. Though the temperature has recently decreased to the point where pipe-freezing could be considered a very low-probability possibility, the heating could not be re-started as the radiators were still not connected after the radiators had been removed to allow the re-plastering to take place. The radiators had not been re-connected as the skirting board would have to fit behind the pipes connecting the radiator to the central heating system. A skirting-board, if fitted as a single piece to replace the single piece fitted to the wall behind the radiator prior to the re-plastering, would have to be fitted before the radiator was re-connected.
However, the addition of additional plaster on top of the old plaster (previously covered only by a thin layer of wallpaper) has reduced the available gap between the wall and the pipes connecting the radiator to the central heating system by a few significant millimetres, significant in that a single piece of skirting-board can no now longer fit between the wall and the pipes connecting the radiator to the central heating system. After discovering this, the skirting-board (including the piece just cut to make it the right length to fit along the bottom of the re-plastered wall behind the radiator) was ignored whilst the radiators were re-connected to the central heating system and switched back on so that we have a good six weeks' monitoring-time to ensure the radiators all work properly and that the connections where the radiators are joined to the pipes of the central heating system are all sound and are not likely to leak warm water all over the floor and the properties beneath.
So far, they are behaving, though there was a small glitch in that the protruding key-knob thing by which the exit valve (or lockshield valve or whatever it's called in official plumbing-speak) of the bathroom towel-rail radiator (which wasn't physically disconnected during the replastering but which was turned thoroughly off when the central heating system was disabled to allow the other radiators to be disconnected from the pipes of the central heating system) snapped off when I attempted to open it when gingerly re-filling the system and testing the never-disconnected radiators before opening and re-filling the emptied radiators. Hopefully this is still within the guarantee of the central heating system replacement-work and hopefully will not require too much radiator-drainage to have to take place, even if it's the most-easily-drained radiator seeing as it's mere inches from the bath.