Confessions of a Newbie Rider

[Simon.Pieman]

Block shifting is also recommended by the IAM as part of "sympathy for the machine" ie it saves repeated use of the clutch when it's not required.

I think the IAM are talking out of their butt. By all means change down the box using the method of your choice, but there is no need to invent silly 'alternative' reasons for doing it.
No mechanic or engineer (me) would advise someone with a worn clutch to refrain from using the clutch on downchanges in future. Clutches wear out for a number of reasons, (usually abuse) downchanging is not one of them.
I applaud the IAM for educating the great unwashed (as they probably see it) but they don't do themselves any favours sometimes.

To paraphrase, the IAM could save wear on their reputation by not using repeated use of bollocks when it's not required.