One of the amendments being debated is from Chris Bryant sayingthat the May's deal should not be brought back before Parliament. I assume the reasons will be those in Erskine May. I would be very surprised if that amendment were to pass, but if it did I think Bercow would find himself obliged to require a more significant change than the "change of advice" fig-leaf. Even if rejected, it may mean bringing MV3 becomes the final chance: MV4 could find itself ruled out.