Problem sorted.
Removed the raspberry pi machine as it appears to be slow in uploading the sketches and allowed a time delay ,which interfered with the serial monitor trigger.
Everything else remained the same and worked…t
There remained an issue of some error messages on upload but it was overcome by re selecting the Wi-Fi port just as the sketch was finished uploading to arduino.
Light are now coming on and off as desired.
Look forward to more projects now and hopefully adding future ( shorter) and more specific posts in this forum at a later stage.