I don’t really get why BA have a 06:25 flight during the winter, it’s just too early. It eliminates all connections and isn’t very leisure friendly at that hour. I am based near LHR but am actually considering the treck to LCY just to get a late morning flight.
By having the flight so early, you also get a few departures from BHD around the same time in the morning. The LHR nightstop leaving Belfast at 7:10 and then the other LHR service at 8:30. Plus the LCY nightstop going at 06:45.
I think a LHR departure about 08:20 would be better but that’s up to BA to decide.