BA are not reducing because their shuttles are full. Pax are just getting to places via the many other options available from MAN these days.
The loadfactor on the Shuttles has been higher than it has been for a long time with the early BA1371 departure proving to be increasingly popular so was surprised to see them drop it for the summer. We had 2 nightstopping BA A321's yesterday - both left with over 200pax each.