As an amateur, and quite happy to be corrected, would it not have been wise to get the aircraft on the ground at the nearest suitable airport as soon as possible?
I understand the argument about being familiar with the airfield, but surely a professional pilot should be able to divert to an airfield unfamiliar to him if the need arises?
And if he was within a short distance of Derry, then BFS would be available with a good runway length, the associated emergency services, and in a very short time-frame?
Saying all that, any one man landing in a big jet is to be applauded...