Well, it’s just decided it will work!!! I previously took a number of photos with the mirror function on and off and they all looked the same, but now it does reverse the captured image automatically. I perhaps should add that the main reason I performed a full reset this afternoon was because the phone failed to ring (make a sound) or vibrate on an incoming call, or play a sound when a text message arrived, despite my having selected ring tones etc and turning the volume to full. That’s now sorted itself out as well.
Thank you very much for taking the time to respond to me so quickly. Very helpful.