@Bowie fwiw, it is a known issue when using powerline adapters alongside VDSL services. They either coexist happily, or do not in your case. Powerline signal transmitted on your AC ring mains is on...

@lordlance "Can two fibre wires be installed for the same connection from the roof?" I don't understand the question? Only one incoming fibre connection can be connected to your ISP router. You may...

@FunsizePhil One adapter (let's call it master) has to be wired to the ISP router (via a switch) for access to the internet. All remaining adapters (let's call them slaves) can be installed anywhere...

@Noab There is the TL-WPA4220-KIT offers a 2.4 GHz wireless extender starter kit. TL-WPA8630P KIT dual band gigabit model offers faster speeds.

@Michaelg72 Yes you can. We used to use PA4010 with old PA2010 adapters. The AV500/600 are backward compatible with AV200 adapters. All adapters will run at the slower speed.

@Steveynet Plug both powerline adapters into the same double outlet AC power wall socket (or AC power wall sockets within same room) and do a speed test over ethernet. Do you see over 100 mbps?