I'm prepare to accept that, on any sensible accounting basis, the presence of those remaining routes adds move value to the overall BA operation than their absence would. But that's not the same thing at all as saying that there are profitable in their own right.
1) LHR base fares are relatively higher than LGW
2) LHR last minute fares are also higher than LGW
3) LGW remains connected to EDI/GLA as part of the BA network
4) Cost base is now relative similar
Given LGW as a stand alone operation has been forced to make each route stand on it's own merits, I would conclude that BA's remaining LGW domestics are likely profitable as BA and EZY are still competing and BA has no strategic benefit in running at a loss. Also given the revenue on the LGW routes is apparently less, LHR-GLA/EDI should be in profit so long as revene allocation to short haul on long haul connections is well managed, it was this that finally killed BFS-LHR.
And if you're British Airways and you can't make money on GLA/EDI to LHR, the core domestic in your own freaking home market,you really should just give up and go home now.
flybe are not helped in that EDI consider them a second tier carrier and so bussing is now the norm at both ends on LHR-EDI, whereas BA are more likely to get an airbridge, though my last B767 up ended up parking on 212 at Cargo.....