BA will be a smaller carrier with no quads at the end of this. I see no business case for resuming B744 or A380 operations. In such a world, the LGW based B777s would be consolidated to LHR and certain short haul LGW moved as well with the rest closed. I suspect the G-GAT* A320s as oddballs would also go as simplicity is sought.
I would also expect to see JER moved (back) to LHR and UK domestic to get some love again, as people scrabble for a stay at home holiday.