I soldered a BPW85C photo transistor onto some CAT5 cable, and connected it to an input on the QTI module, which is near my electricity meter. I was able to lodge the cable in a suitable place to ensure that the end of the photo transistor is right in front of the flashing LED on the meter.
1,000 pulses of the LED = 1kW. Cortex has a pulse meter object, and it all worked first time!
I’m currently using 3.96kW, and will add some graphs once they’ve populated.