Hi,
The pair of Tp-Link Deco P9 arrived yesderday. I removed the Devolo units and place the two Deco units in
exactly the same location yesterday afternoon. It's been just over a day and the reliability has been absolutely fine, but time will tell.
The speed is MUUUCH better on the first floor. The WiFi speed matches the wired speed; Wired (PC) = 250-300Mbps, Wifi (phone) = 250-300Mbps
The wired and WiFi speeds on the ground floor are also the same as each other, but much slower. The TV is connect to the P9 by ethernet cable. Here
Wired (TV) = 50-80Mbps, Wifi (phone) = 50-80Mbps. I think this is understandable because the distance and structures (old house with solid walls) between the 1st floor unit and the ground floor unit prevent the best WiFi (even with meshing magic), and powerline, as has been mentioned, has it's limits. Perhaps with one more Wi-Fi-meshing P9 unit, placed strategically on the landing or hallway, the WiFi may be improved, but TBH, I'm happy if things remain as they are.
I've installed a nice, useful app (Analiti) on my Android TV that I've set to perform a speed check every hour. You can call up historic data so it's an easy way to log the speed and reliability on the ground floor.
I'll post again in a few weeks to update on the speeds and stability.
Many thanks again for all the input from everyone, and have a very Merry Christmas
