SOLVED - Apologies my misunderstanding of pairing devices e.g. MAC addresses!

From my last post I learned that basically I was running into memory issues by using a Arduino Nano to do too much when I added an OLED display to my particular project. So I decided to begin learning to use the ESP32 boards ( I have 2 versions Node MCU 32S and DEV KIT 1).
I’ve got through some pretty good projects using a Node MCU for example to drive a Mecanum wheel based rover and implemented PWM with acceleration and deceleration, collision detection etc.
SO…moving onto initial steps writing simple Bluetooth commands (turning LED’s ON/OFF) via my mobile phone I was quite happy to see it working.
Then the board started responding erratically when I wanted to upload program variations and ended up that I cannot communicate now with the board over Bluetooth?
I installed esptool and used that to clear the Flash but still this particular board won’t communicate over Bluetooth.
I’ve swapped the board with another ESP32 NodeMCU 32S and it works fine in communicating with my mobile and responding to the commands when I transmit ‘1’ ‘2’ ‘3’ etc.
My question is what could I have possibly done that seems to have destroyed the onboard Bluetooth functionality???
This is the platformio.ini I am using

platform = espressif32
board = nodemcu-32s
framework = arduino
monitor_speed = 115200

Any help or advice where to look greatly appreciated.