BA214 Boston-London is diverting to Shannon. Looks like they positioned in a frame from Atlanta (cancelling ATL-LHR) to operate it last night so crew likely do not have hours to reach London as they left past 2am local time. Aer Lingus went at 09:50am so likely couldn't get the crew there on time for that one.

BA214 was a replacement for BA212 which was a cancelled LHR-BOS-LHR A380 so wouldn't have been a 777 crew in Boston to take it to London