Sad to see TN depart. She was I believe the last ex CityFlyer ATR that regularly still visited LGW. I had the privilege of working on her from new.
I don’t know if BA still bring some of the ex CityFlyer RJ100’s in to LGW. If not all the links with the old CityFlyer are now gone.
Regarding the rearward facing seats this isn’t unusual. We had an old ATR42 with these fitted taking capacity up to 50 rather than 48. If there were two cabin crew on board one would use the FD jump seat if it was full.