We've taken the BA BOS-LHR daytime flight and like it quite a bit. VS did have a competing flight pre-COVID. I believe there are day flights out of JFK and EWR as well. In the summer, we actually were able to connect onward in LHR without overnighting, arriving in BLQ around midnight. There was an option to MXP as well. We were traveling to Italy so I didn't check other countries. Might be worth your while to check.