LHR WW and LGW Fleet both work to 900 hours per year so any costs savings made by making crew work harder will be offset by having them grounded for 2/3 months of the year because they have reached to 900 hours before the rolling 12 months is up.
However Eurofleet only seem to manage on average 500 hours a year, so looking logically at cost savings the only option seems to be to make eurofleet crew work closer to the 900 hours. Another 400 hundred hours per year from crewmembers would generate significant cost savings.
Although cost savings could be made from other fleets ie: removing crew members off longhaul aircraft this effects the level of service given onboard and with flights crewed to the bare minimum anyway this would have a significant negative effect on the BA business plan to be a 'Global Premium Longhaul Airline'.
Having a 'Cabin Service Director' on a single aisle aircraft is just to operate shorthual services and having above minimum crew on the A320 series aircraft can no longer be justified.