O-D, I am not sure what you found to disagree about apart from the Sir-Col bit.
Now a friend of mine, former WO1/Captain, always calls me Sir when he visits. I have known him for 10 years and he worked as my contract manager for the first 4 of these!
The 'Sir' bit or 'Colonel' bit is probably as much to do with Service as manners. Would you seriously drop Group Captain in to the conversation as less formal than Sir?
Now our brown bretheren may be happier with Colonel or General rather than Sir and Colonel Bob is certainly the norm rather than Group Captain Al.