So the heating has not been fixed. It turns out that British Gas is comprised of bureaucratic faffsticks who will choose to replace at least one part that does not really need replacing, return TWO DAYS LATER to replace a second part and then decide someone else will have to stop round some other time altogether to rewire the entire system.
However, due to some obscure British Gas policy, we won't be able to get a rewiring engineer to look at it and sign us off onto the WAITING LIST to have our boiler rewired until January at the earliest. And the last faffstick boiler engineer to show up at our door informed us that we will likely be looking at the end of January before there is any rewiring done at all. Further to all that, we were told this morning that British Gas might in fact deny all responsibility of the boiler and direct us to the manufacturer and the person who installed the system in the first place. Nonetheless, they would be charging our landlord for all three visits and the two unnecessarily replaced parts.
As a parting gesture, Boiler Man gave us a fan heater he had in the back of the van. Matthew was rather touched by this until I pointed out that we get our electricity from British Gas as well, and as the fan heater is about as economically viable an option as flushing a toilet with liquid gold, British Gas wins again!
So, to recap: British Gas 4 - 0 House of Erqsome.