Maybe you've just discovered you have a radio amateur in the vicinity? :)

It's amazing what 400 watts into a well-matched dipole on 3.5MHz will do to a powerline adapter ... anything up to several hundred yards away.

I knew I shouldn't have sold my FL2100B :{

FOR

Just as an aside:

I needed to run a cable from one end of a house to the other. The floors and ceilings were concrete, so no easy option and strict instructions from 'the management' of no unsightly cables on display.

I discovered that if I eased up the edge of the fitted carpet there was a gap between the gripper strip and the wall which just fitted a cat 5 cable. The gripper strips provided a degree of physical protection to the cable. The only wrinkle was going through the doors where I had to nick out the metal gripper strips with a pair of tin snips. If I had had a flexi drill extension I could have probably drilled horizontally through and completely hidden the route.

EG

Well, the attempt to pair Netgear and TP-Link produced very mixed results. A basic TP-Link unit (single ethernet output) paired with the Netgear straight away. Thinking I was on a winning streak I then decided to try to pair the Netgear with a TP-Link wi-fi unit. The two absolutely refused to talk to each other. I thought about exchanging the Netgear unit connected to the router with the TP-Link to see if I could get the 2 TP-links to talk to each other - but it's Friday and the pub is open......

One step forward, one step back.

Could be that they are both fighting for the same ip address. They're both typically in the 192.168.xxx.xxx range. But if they are both wanting to be called 192.168.0.1 for example, they will never be on speaking terms. Their native addresses should be on the id label of each bit of kit.
Alternatively they could be wanting to be on a different subnet. I recently had a repeater which wanted to be 192.168.2.1. Had to reset it to the '0.xxx range, then it worked perfectly.
hope this makes sense?

Been there, Jim. One cheap eBay WiFi unit seemed to work but I couldn't find its address to "talk" to it to change the SSID. It was Cat-5 connected to the router and provided WiFi connection from the garden.

Eventually a sniffer found it was using 192.168.2.254 and nothing in it could be changed. It's in a box out in the workshop now.

The simple principle is that despite all standards, it's rare for one brand of wireless networking kit to play well with another brand. I've become very adept over the years at pulling cables and then fitting Cat 5 plugs on the ends.