Thanks AerocatS2A and Rick777 for your esteemed input. Rick777, depending on your load sheet, FL410 normally prevents traffic conflicts.
crispey, I am aware of the direct centre line fix at Manchester from deep down in Germany. It routes them over Suffolk, Norfolk, etc.
As for direct routing from ATC, I remember the Polar route carriers getting; "Direct to 61° 10.'" 15 minutes out of Heathrow.
chevvron. Good evening, sir. I think what you suggest is the answer I'm looking for. Why are upper airways 10 miles wide? You can do barrel rolls........................ as long as you stay in controlled airspace.