↓ Evelyn’s Response
Biscuit has not imagined anything. Lurchers in particular have an almost administrative relationship with the inexplicable — they log it, they route around it, they do not dramatise. The fact that he has established an alternate path rather than barking or scratching tells me he has assessed the situation and reached a sensible accommodation. He is, in this respect, ahead of most people I hear from.
The breathing is the detail I want you to hold onto, and specifically the quality you described — patient, long-settled. In my experience, whatever takes up residence in the airing cupboards of Victorian terraces does not do so recently. It has almost certainly been there through several families, through the conversion to a bathroom, through whatever was there before the bathroom. You are not its first housemates. You are, if anything, quite far down the list.
