In reply to Alan James - UKC:
Alan, I think there's still too much emphasis on the 'long falls can be safer' schtick. On the second diagram you say:
'a longer fall of 3m, the fall factor would be only 0.15 - significantly less - and safer' (than a 2m, factor 0.2 fall)
The difference in fall factors here is not at all 'significant', its slight. In reality other factors would become more important as to which is safer. I think you should drop the second diagram and just explain fall factors before trying to introduce the concept that sometimes a longer fall can be safer.
I have to teach this to industrial users most weeks so I have some experience of confusing folk!