For what it's worth, there were reports in the Columbus media 2-3 years ago verifying CRAA was in talks with BA about service. The story about "London nonstops" then popped back up at the start of 2016 on the local ABC affiliate (WSYX).

A BA 787 would be too much airplane for CMH, but an AA 757? Might not be a bad place to start. AA has actually gotten around DL to become #2 in market share at CMH behind WN.

edit- Come to think of it, there have been ongoing renovations at CMH for about that length of time. Maybe that was a holdup?