Super-thanks for your answer, what you say makes sense, to avoid connecting to the wrong wifi extenders. I'll check these.

would I be able to plug my upstairs computers to Ethernet RJ45 ports on these?

I’m thinking of two options: This one would be best as it’s cheaper: TL-WPA7517 KIT TL-WPA7517 extender TL-WPA8630P extender (with AC passthrough) or the more expensive: TL-WPA8630P KIT 2 x...

I have some doubts and would be very grateful to get any expert advice: I live in a relatively small 2-storey house in London. I’d like to plug a Powerline adapter (or more if at all possible, this...