Plusnet Hub One - Disable NAT or Enable Bridge Mode?

[#1]

Regrettably I'm not a mind reader and don't know the layout of your house  You could test the Pi by moving it to where router 2 is perhaps?

If the Windows PC is behaving correctly ignore anything to do with router setup and concentrate on getting your powerline adapters working...

[#2]

The pi works fine when connected to Router 2, but then again that's directly to the router without the powerline.

The powerlines work fine when I connect my laptop to it, so I can't understand what's going wrong.

Moderator's note by Mike (Mav): Full quote of preceding post removed as per Forum rules