Fun fact, I helped a friend of mine book a *A dump on a different alliance airline site as OTA, dump worked.
Two months later, airline OTA calls him to ask how did he price that out, as it seems an error to be able to book *A on their site, and one of the flights was cancelled.
He said "i clicked on google flights", ended up being moved to that specific airline in a Y fare, as the airline couldn't re-book him on *A.

Not really contributing much here, but keep it in mind, sometimes the risk is worth the reward.

Also for noobs still figuring out from a couple days ago, it is UA from LON on a $80 bf.