Thank You so much for replying and advising me of the the pros and cons.

I can see that debugging the solution is challenging but it does seem like an ideal setup to replace my current NodeMCU 433mhz to MQTT gateway which only supports my own custom message format.

Regards,
Sheridat

Hello, There is a board available that combines an ATmega 2560 with an ESP8266 WeMos. Effectively the serial output from the "arduino" goes to the ESP8266. Has anyone used one of these boards as the basis for an RFLink Gateway to communicate with a Raspberry PI over TCP/IP? Here is a link ...