I really don't understand the rationale of BA and the LHR route. The decline is relentless, but I am not convinced it is down to lack of demand rather than a concerted effort on the part of BA to reduce capacity; but why ?
I fly the route twice weekly. Invariably, both ways, it is announced that the flight is full, be it an A319 or A321.
So why does BA not schedule an A321 on the 319 routes which are always full ?
I think the success of domestic Club Europe has caught them somewhat on the hop; many times on an A320, the curtain can be back at row 12.
One can only hope with forward planning, next year's schedule sees more A321s on the route.
The demand is there; BA just aren't meeting it right now.