Thank you for your reply and yes, its most helpful , With been such a long flight, We are going to avoid the window seat since your always disturbing the person who will be sitting in the aisle seat if you need to go to the Toilet , So my wife and i will opt for 2 seats next to the aisle ( B & C or D & E)

I am looking forward to the experience of flying with Cathey, I will just have to remember to change the loyalty Card scheme from Cathey to BA in order to get the Avios points after checking in