Just a quick update today...

Node 0 has now been built and programmed, picture to follow shortly. It is comprised of an Arduino nano and a NRF24L01 with a SMA Antenna. This will be permanently connected and powered by the server (currently a PC).

My Raspberry Pi 2 has just arrived today, this will be used as a server once I am happy that everything is working correctly. I have chosen this due to its low power consumption and compact size.