The simple solution is to close the company down and start again.
The slots do not belong to BA: they belong to ACL who allocate them/ No doubt they would allocate the BA slots to the all new British Overseas Airways and to the short haul fleets in British European Airways.
New contracts, new working practices, lowr salaries, higher productivity an a reinvigorated business model an vastly improved service.
Instead of trying to be a hybrid LCC stick 2 fingers up, charge a reasonable fare and DELIVER!