This is a crisis
Thanks for taking the time to do the bookwork and come up with the official answer!!
It would appear from reading your quote that in order to comply with the requirement not to give clearances to cross red stop bars, controllers will have to stop giving conditional clearances. The reasoning behind this statement is that if the condition has been fulfilled and the stop bar has not dropped then the ATCO has (albeit unintentionally) cleared an aircraft to cross a red bar.
(I am partly playing devil's advocate here, but mainly to point out that what is written in our manuals is not neccessarily easy to apply in real life).
G W-H