They had let off for a month but since my trip out to the health centre they are totally back. I suspect the trip totally stressed me out (I woke with a start at 4am).
I have bought fire alarms and I know I should just trust them to tell me if a burning smell is real. But I find it incredibly hard not to to act with panic and alarm when I smell fires
Update: I think maybe with the colder weather people are firing up their coal fires. That always produces a sooty smell at first. Hopefully I am just smelling that