Much sympathy - something like that has happened to me/us several times over the years
That's why we still have a "backup" gas fire in the lounge (which has been on low heat for the last 48hrs in addition to the c/h - first time this, and possibly last, Winter!), a gas hob in the kitchen and several fan heaters (in the attic) - all of which can provide some "local" warmth if needed. "Diversity" and lots of insulation do help.
Edited: just remembered that there's also the bottled-butane space heater in the garage - old, battered, ugly, but it still works very well!
PS: have you tried giving the "big Honeywell valves" (which I assume are those which control the h/w from the centralised heating supply ?) a few "careful taps" with a hammer as they can sometimes move but no water comes through because of a local blockage in the lockshield ends of the valves?
I ran into that problem at home several times - and then on the houseboat on the Thames in which a nephew & then g/f were living and the bedroom at the bow was freezing although the rest of the system seemed to be OK (and you seem to be at the end of the block, and thus in a somewhat similar situation). So, I borrowed his small hammer and tapped firmly away at the body of the valve for quite a few minutes until the entry valve loosened a bit, and then hot water came through - he always remembers that, and sometimes has asked me to "fix" a c/h problem in other places he has stayed, but I politely "declined"!
me mad I would still like to know who carefully carved that masterpiece of impressionist expression
it really does help.
