It is hardware and it is sort of OEM related. I have been looking at ESPHome and realised it has native support for the temperature sensors I have. The BLE data via the RaspberryPi is a bit erratic and the Pi locks up when one of the BLE calls is made (obviously a blocking call in the NodeJS library).
So I thought I’d send for an ESP32 board from China - no hurry!
I know to watch out for the WEMOS D1 and make sure you get a genuine one. I wonder if it is the same for the ESP32 boards and if so any recommendations?