VsFsm_Oct1990
It may well be a VS SOP it is not a BA one. I happen to think it is a smart thing to do, but then I think that there are a lot of smart safety related things that people don't do.
You are correct in your analysis wrt the ANO and the Captain's authority. What is more difficult is when the CC decide to tell you to do it for take-off and landing and it is not a company SOP - at this stage you have no way of knowing whether it has come down from the captain and is therefore a legal command or whether the CC on the day have had an idea and it then has no legal authority. Either way I guess it is easier to comply than potentially act in a criminal fashion, ignorance is no defence in English law.
Tightslot
You got it spot on about BA, the "not invented here" syndrome is very much alive and well at BA. As far as management are concerned they are the only ones who know anything about aviation. Just ask an Airbus pilot about the autothrottle!