It would be very optimistic, or educationally naive, to imagine that we could find one definitive method for multiplication and division and that all children could successfully learn it that way.
Finding the most "efficient" method may be an easier task, but there is a difference between efficient and effective when one considers the individuality of pupils. The chunking method often requires more steps but that may be a trade-off for other disadvantages that some children experience, most notably the tendency not to try the task at all if it is considered "too hard".
That was the less worrying part of the article. The bit that is truly fascinating is the way in which children and teachers will be encouraged to take a narrow view of learning maths. Children's efforts will be judged on a basis that can be summed up as "no marks for thinking differently from me". I feel that we are entering an almost Orwellian world where "Orthodoxy means not thinking - not needing to think".
Steve Chinn, Bath.