[en] Technology developed for the T2K electromagnetic calorimeter has been adapted to make a small footprint, reliable, segmented detector to characterise anti-neutrinos emitted by nuclear reactors. Based on the design of the T2K Near Detector ECal, the device detects anti-neutrinos through the distinctive delayed coincidence signal of inverse β-decay interactions using plastic scintillator and Hamamatsu Multi-Pixel Photon Counters. The device has been developed and constructed at the University of Liverpool and is situated in a 20 ft ISO container unit, capable of operating aboveground. The device finished a successful field trial at the Wylfa Magnox Reactor on Anglesey, UK where it was located roughly 60 m from the 1.5 GW_th reactor core and is now undergoing an upgrade with 50% more mass and channels as well as new electronics and sensors. (paper)