I still dont understand what it means by no hiding place from whipping. As reosequartz says on another thread, it can have at least 3 meanings.
And possibly more, those three were just my interpretation of 'no hiding place' in that particular context.
I think if an MP defies the Whip that is probably their chances of any promotion gone! If there is no Whip, as there was no Labour Whip for this vote, the MPs can vote with their conscience - but of course the leadership will know who voted which way and if they vote differently to the leadership there is 'no hiding place'. Chances of promotion gone or demotion in a few weeks and possible de-selection apparently.
It may have been a very clever ploy by JBC to allow his MPs a free vote. In that way he can sort out quite simply who disagrees with him, they may eventually be deselected and he may get the type of party he wants without the moderates.