In reply to simon-pearson:
I wrote the UKC description about 5 years ago. As I remember it both versions finish at the same lower-off, shared with 'Tell It Like It Is'.
The RH version of The Knack is based on the original trad line which joins Tell It Like It Is at about 2/3 height.
I don't have any inside info, just what I gleaned from the guide and from doing most of those routes.