EI-BUD
Historically BA were far more interested in maximising yield from lower volumes than filling aircraft and diluting the yield, the difference is now that you pay for luggage and all manner of other things, so filling the aircraft is more important and more seats (if you can fill them) makes more money.
Although the route Vueling seem to be taking with their high density AIRBUS pushing 186 seats at 29" pitch!! might be ok with the somewhat shorter Spanish clients but won't go down well with leggy Brits