@jiphex James - I tracked you down and have joined your IHD. The signal strength is quite low - if you have any issues please move it closer to your Electricity Meter.
@IrregularExpr You need to have an IHD/CAD to get mqtt.
You can have DCC only data (ie 30 min data for free just download the Bright app and install it (https://t.co/R4BhaydZXH or https://t.co/tCgb8LdBQO) . With this you get api access.
If you want closer to realtime data you need the the IHD.