Globaliser
Frequent Flyer miles don't enter into it as far as I'm concerned, unfortunately... You may well be right about the class, though going from a cheap cityexpress ticket to a cheap bacon ticket means the change will be merely one of nomenclature. (Further investigation shows the class to be 'domestic', the same as before.)
Interestingly, I looked at the booking through the manage my booking link on the BA website and I can't see a single thing that has changed. It still shows the flight being operated by British Airways Citiexpress. It isn't letting on as to the aircraft type, though...