The issue 2 boards are here, I’ve soldered them up and tested them and the good news is that they match the performance I managed to prototype with the issue 1 boards (thereby rendering all the effort I put into making the supplies easy to isolate pointless, ah well!):
Sleep mode current (10.00 seconds): 0.00147 mA
Active mode current (0.060 seconds): 8.97500 mA
This equates to an average current consumption of 0.0559mA, or 55.9uA. This means that a 200mAh battery will last (hopefully!) around 4.9 months.