I'm using the 500 AV Wireless+ units
What units exactly are they please?
In the power socket by the router, I have a Devolo dLAN 500 AV duo+
In the power socket elsewhere, I have a Devolo dLAN 500 AV Wireless+
I bought them as part of the Devolo dLAN 500 AV Wireless+ Starter Kit, which is this item at Amazon:
http://www.amazon.co.uk/gp/product/B00A67I5EKNot cheap, though mine was £95. Worth noting that the ethernet sockets are 10/100 but not gigabit, in these models.
The router (Billion 8800NL) is plugged in via the pass-thru power, but nothing else is.
The Devolo's report speeds between them at 220Mbps (from router to remote) and 250Mbps.
However, when performing speedtests, I'm limited to around 56-60Mbps downstream, when a direct-wired laptop can get ~75Mbps.