This!It is a bleeper when that happens - in our last house the boiler broke immediately and it was 2k to fix it - but see how she had someone round to sort it out asap? A landlord sorting it out, not so much. Getting them to actually buy a new one as well rather than asking the plumber or whatever for the cheapest possible fix, again not so much. You get more control over it at least and tbh the cost of a new boiler will be a drop in the ocean for Dimbo. In fact, I'd start putting bets on at how long it is before we see ads for some boiler company...
A month after we moved into our last flat the water in the kitchen wouldn't drain and the landlord refused to pay more to have a plumber come after hours or on the weekend, so it took them more than 10 days to fix it. All of this was apparently justified "because you still have water in the bathroom". We even offered to pay for the extra charge for them to fix it quicker and nope. I can guarantee that in their own home people would pay the extra amount to be rid of a backed up kitchen sink and dishwasher. Guaranteed.
And it's not like she can't afford a possible repair like this, so my sympathies for homeowner Slyomi are 0. She will however probably take a vacation to recover from all the stress this caused her