I think I need to buy a powerline adapter with wifi and passthrough sockets. We get very little Fast Broadband signal and even less WiFi connectivity here and the devices are spread out across the property.

I need to be able to extend the reach and speed of both, so will need a starter kit and also add on plugs.

Do the add-ons need to be the same model type as the starter kit? And where can I get them?

As we only have very low signal here what level of adapter should I be buying?

Our estimated downoad speed is 11-18mbps, we often get less than that, especially now we're all working from home. Our use is home working, internet browsing and TV streaming, we are not game players and attach our phones to the WiFi where possible. The property is single storey but spreads across a very long footprint and there are walls blocking. All devices are well away from the Master phone socket & router and there don't appear to be secondary phone sockets anywhere to move the router to.