@mfalkvidd Thanks. The sensor (an LM393 light pulse sensor) and the radio seem to consume about 12mA each (at their respective voltages).

To test the sensor / gateway / controller combination I powered the sensor with a 9v battery. Looks like after about 12 hours it stopped transmitting (although the units lights are still lit) but guess it lost power to run.

Will have to think about long term power as thats clearly not sustainable. However, it all seems to be working so the major learning is going well!