The design has finally been captured in KiCAD. The design is effectively identical to the prototypes but I added in some extra features. There is a snubber for the relay output if the MOV has issues, I also added the ability to power the ATMega from 5V or 3.3V in order to avoid the need for level shifters in various projects.

I added a buffer to the NRF24L01+ in order to deal with the potential "shifting" which can now happen. This also increases longevity by not using the 5V tolerant inputs. A side effect of this is increased power rail range, so you can drive the module off of 3.3V too!

An isolated DCDC is used to drive the relay in case of relay failure coupling back to the MCU power rails which are accessable by the users.