Strong smell of boot polish in the house...any ideas?

[LadyCelia]

I woke up in the early hours of this morning, and there was a really strong chemical smell coming from downstairs - the closest thing I can think of is the smell of shoe/boot polish. We've searched everywhere for the source & can't find anything leaking. CO2 detector is working & is fine. Does anyone have any ideas what this could be? Should I just call out a plumber to check the boiler (though the smell wasn't coming from that side of the house, more like from the downstairs loo) or could it be electrical?

We opened all the windows overnight (brrrr) and the smell has lessened this morning, but I'm worried in case it comes back overnight again.

It's a ghooooooooooooost! Ex army, obviously, hence the polished shoes.

Maybe something the neighbours put into their toilet to clean it and it's coming up through yours?

could be the insulation on an electrical wire or fitting that is heating up and may catch on fire!! It could be a light fitting - especially if you recently put in a higher-power light bulb - or maybe a ceiling pull switch as they do wear out with use over time, so the contacts can burn. This is can be problem with ceiling switches for electrically heated shower units because they take such high currents. (Amps).
Wall sockets check too, I would get in an electrician

At the least get a smoke detector for downstairs room and close all doors when going to bed ,until you resolve the problem.Not saying it is electrical but you can get a similar smell to boot polish from the insulation of wiring when it's getting hot.I would give it priority to get an electrician in to just check the sockets ect out

Long shot , check you have no rusty aerosol cans leaking in kitchen cupboard under sink

What did you ultimately determine was the cause of the shoe polish smell in your home?