@Reptiled Hello, 

If House Leds are ON on power line units , you could try some suggestions here:
1> change a different Ethernet cable between Main router and main power line adapter
2> try a different LAN port on main router. 

If still the same problem,please connect a computer to router by Ethernet cable ( same cable that main powerline adapter is using) and check do you have any Internet? Please send us a photo of the IP address then. 
How many Leds are ON  on the main adapter and powerline extender? 
If connected to WPA4220 the wifi adapter by WiFi or by wire, what is the IP address & Gateway on your computer? https://www.tp-link.com/support/faq/838/

Thank you

@Reptiled  Hello, 

From the photo devices get an invalid IP address. 

1> Did you connect a computer to router by Ethernet cable ( same cable that main powerline adapter is using) and check do you have any Internet?

Please send us a photo of the IP address when PC wired to router. 

2> Factory reset power line device ：      

Reset Wired Powerline unit:

Press the pair button for more than 5 secs until most Led flash once    

Reset Wireless powerline unit: 
Press and hold the Reset button (or use a pin to press reset hole) for at least 5 seconds until all LEDs will turn off and start on again.   

After factory reset, do not pair them and please check what is the IP address when connect to wireless unit ?

3>Put them into same room,  repair both unit and check if they work in the same room.