The cable that went up to the thermostat had brown, blue and black wires. Closer inspection of the block and it had symbols for where to connect the neutral and earth, so it was just a case of which one was feeding the live to the thermostat. I went brown- brown in the logic that the black would be the compressor feed. Plugged it in, and when you turn the thermostat from 'off' to one of the levels, the compressor starts up, and switches of if you turn it back to 'off' so that all looks good. Left it on in the garage to see if it gets cold. Thanks for all the help.