My investment has arrived a nice little Wemos No NAME D1 mini EUR 5.59, for pennies.
SSD1306 OLED 0.96", EUR 6.46.
I also discovered that you can use a slightly different oled begin call to use my old SH1106, but there are some artefacts.
Works perfectly with version 1.11 development with my hardware, (MLX90614, BME280, TSL2591, Davis anenometer, OLED)
Had to figure out that the pins have a different numbering to the arduino.
So this confirms problem on older hardware is not a wireing problem but most likely a short of memory problem,
I will let it run for a few days to see if there are any crashes or bugs, that I can see.
Then I will try with the RG-11.
As promised I have developed a slim version for the arduino UNO, which is free for perusal on github, the code is very simple
but will work with the sensors above (didn't try OLED) and not crash the arduino.
I got it to talk with indi after I figured out the firmware version number must be surrounded by ".
Now that I see how nice the wemos is, I will try to build my next station (no leaks!) with it.