Thanks for that update Auky - I'm sure a few co-pilots will be wringing their hands in glee!
Seriously, though, I think a change so significant should have been transmitted as a CAA Information Notice, as it has several implications.
I agree that the AMC sections 4&5 cause confusion - if they are intended to be aircraft only then they should form a sub-set of item 2. By listing them as they are, the inference is that section 3 (FSTD) is also part of the overall concept of Flight Time - which is what FCL.050 is dealing with.