Powerline devices should work in a pair as least.
Did you refer to TL-WPA281KIT? PA2010 in the kit will be connected to the main router and WPA281 can be placed in the room where you want to boost Wi-Fi signal.

M Diamond wrote

Powerline devices should work in a pair as least.
Did you refer to TL-WPA281KIT? PA2010 in the kit will be connected to the main router and WPA281 can be placed in the room where you want to boost Wi-Fi signal.

I have a couple of tp-link powerplugs currently running throughout my house, what I want to do is have my wifi available in the summerhouse at the end of the garden, it is out of the range of the router and i have tried an extender which didnt really achieve much, so my question is if I connect a TL-WPA281 into a socket it the summerhouse will it clone my wifi from the router in the main house or does it need to be within wifi range and is basically an extender with powerline ports?

You have to able to add WPA281 in existing powerline network first.
http://www.tp-link.com/en/faq-258.html

If you press the button to clone Wi-Fi, you'd better place WPA281 and your router next to each other. If Wi-Fi is cloned successfully, no need to be in your router's Wi-Fi range.
But If there is no WPS button on your router or it is inconvenient for you to press the button, you can follow the guide below to change wireless settings manually after you pair them.
http://www.tp-link.com/en/faq-398.html