Thanks for the reply. Recently I had a chance to look closer at the aircraft.

I noticed on the metal leading edges, on the underside, there are a row of holes about a centimetre in diameter which are only on one or two of our planes. What do you think these are as I have no idea?!

Also when we refuel I am consistently seeing an over reading of the fuel tanks of about 100 kilos every time, do you think this is important?