Well it's been quite some time has passed but I've finally got around to finishing this up and have now released the devices on Tindie and my own personal store.
I have setup a discord server to discuss the board and if people have any feature requests or other feedback they are more than welcome. Discord Link
This is the latest release and represents a shift from the passthrough method to a new style of the ESP8266 extracting the data which is viewable locally but then is also possible to post this to an MQTT broker or influxdb database.
For flashing i would recommend using the application esphome-flasher which is a great tool for writing the firmware and it has a version for most OS's. It can be downloaded from Link
The firmware is available from Link
I have created a 3D printable case which is on thingiverse. It's a snug fit but once it's in there it won't shift and the RJ45 socket ends up nice and flush with the case. You can download it at the following Link