I'm not using interruptions at themoment, so I receive messages in the ESP8266 every loop of the main program (every 10s)

I've resolved this using persistence in the MQTT messages sent to the ESP8266 (messages that at the moment just turn on or off the led on the ESP). So... it works. It isn't the best way, but it just does.

I'm sure this could make use of interruptions, but I may need some help with that.