LBA-LHR was predominantly used for connections. Hence reason if BA decide come back I guess they would operate that mid morning rotation again.
Like
@KARFA has said it will also depend on more long haul routes especially to the Far East and Asia reopening up sooner rather than later along wih that slot wavier at LHR be removed.
If I'm being honest
@Bobby2000 I can't see a night stopper happening if BA do come back because the way they operate and advertised the route in the past.
Yes APD on UK Domestic flights being reduced has to be welcomed. But you have to consider all the extra costs involved which would mean fares have to increase making the whole operation unvaible. Eg Crew have to be put in a expensive overnight hotels, transfers from/to airport, use of prime time morning slots at LHR and so on.