So, inside the birdsnest are two systems:
(1) bus pirate and SX1276 inair9 LoRa module
(2) Carambola2, SX1276 inair9 LoRa module, bmp180 barometer, DS18B20 temperature, RTC, etc.
I realised that I can write code in binary mode to drive the bus pirate, which means I can write software to run on a laptop to pretend to be the farm base. Although as a diversion I managed to write code that claims to compile into 1020 bytes for an ATtiny13 to act as a serial - SPI bridge :-) I just need the ATtiny13 to rock up in the mail so I can see if it actually works!
I also managed to get SPI over GPIO working on the Carambola2 as the fencepost station, to talk to its SX1276.
So for a while now there should be more software going on than hardware, although I need to do something about the birdnest so I can put a module out in the paddock. Hmm, a circuit board might help here...