Many thanks for your prompt response. Excuse my ignorance but does a power line adapter require a connection over the same wiring ring? ie: my power upstairs is on a different circuit to downstairs. As I am trying to increase my wi-fi signal downstairs and my modem is upstairs is this a viable option?
I have a trial set here. They perform fairly well on my old electrical wiring, getting around 120Mbps to 170Mbps on a Ethernet conection. However, the speeds will depend on the condition on your home's electrical wiring and the amount of electrical noise present.
On the downside, they are not pass through, meaning you will need a spare electrical socket for each adapter.
On the wireless side, they are single stream adapters. So realistic speeds would be around 35Mbps on the 2.4Ghz band (Using 1 wireless channel), around 75 Mbps on the 5Ghz band (Using 2 wireless channels ) and around 200Mbps using wireless AC, assuming you have wireless AC capable devices.
Obviously, these speeds will depend on your wireless environment and interference from other wireless networks and domestic appliances can drastically reduce these speeds.