I was also thinking JA and not Steele. But your post made me think about this:
Maybe there are even more characters in this play. I doubt that Steele is the only person in the UK with knowledge of the plot! He’s just the only name I have on my radar at the moment.
I expect there must be several people inside the British government and/or intelligence agencies who have been involved.
Do you think all those Q pictures taken in London of LP & PS (or whoever was in them), do you think all those Americans went to London to meet just one person? I’m not ruling that out, because it could be. But a commonsense guess would be that if a bunch of people need to meet in person, then the smaller group would fly to the larger group. Of course that would not be the case if there were something special about the location that made it necessary to be there.
... needs more contemplation.......
.
Plenty of seats on the plane! ;)