Indeed I agree the whole 'all the business pax go to Heathrow' quotes that get regularly mentioned on here are rather exaggerated. I believe Southampton actually has a higher percentage of business passengers than Heathrow (40 something percent from what I recall)!
I agree it has been well proven that Heathrow is where airlines tend to make the most money but also think this tends to be a little over emphasised at times.
Back to BA, I'm curious to know how the remaining ~4 slots from the additional 777 at Gatwick will be utilised. Also, is there any confirmation of what exactly BA have done to improve the economy offering on its 789's. I've heard of slightly wider seats and narrower aisles and also a 32'' pitch throughout?
Also read on FT that a few economy rows of the 'Super High J' 747's will have their pitch reduced by 1-2'', seems a very risky move given the feedback on the 788's.