"It will be interesting to see what will be set up for a diversion point at LHR for what ever reason. Does the 789 have sufficient capacity for a flight that long and have 30mins plus holding fuel?"
You wouldn't announce / pursue it if it didnt work right?
And I'm with RodH. no way I'll be on it!!....especially in Y .... I far prefer to drift on up to SE Asia on an enjoyable day flight, and hit Europe from there, similarly, coming home, break it up nice and easy, midday to midnight(ish) flight back to East Coast.....and go to bed.....For us, same reason as no flying between Rast coast and Dubai...