Thanks so much for your reply! :)
1. I did try and "downgrade then upgrade" my drone firmware, but this didn't help
1A. When I connected my remote-controller to my computer it didn't give me any options to downgrade the firmware, only 'refresh'...
A few days ago, I was flying my drone, before the I had fully charged the drone battery but NOT the RC1 because it showed full power and I (apparently mistakenly) thought it meant it didn't need charging beforehand.
The RC1 was left uncharged...