The only SOP that really mattered on this occasion was the one that says that under no circumstances do you ever surrender your command. The reality of the situation was that it made our navy a laughing stock and encouraged the Iranians in the belief that they could very effectively continue tweaking the lion's tail.
That is the situation that still prevails. The inquiry report revealed a preoccupation with legal matters bordering on the obsessive. That is perhaps all very well if everyone is singing from the same hymn book, that, however is almost always never the case.
If one expects to be taken seriously - militarily that is - then situations that have a potential for robust threats need a robust response. Then you get taken seriously. 10, Downing St. isn't in the firing line when hard choices have to be made very quickly.