// If they do Johnson will use the Parliament Act. It will only delay by one year. //
One of the reasons this legislation was passed by the Commons without a fuss is that some would-be rebels decided that the Bill was too urgent to kick up a fuss about international law violations. This legislation is "needed" in time for January. So if the Lords do block it then waiting a year would be waiting until after there was any real point (at least for the offending sections 41-45).
On the other hand, the fact that this is going to the Lords so slowly suggests that all that guff about breaking International Law was never even intended to pass, but was meant as a gesture, a negotiating tactic. Threaten to pass legislation that undermines treaty in the hope of forcing the EU's hand. I hope I'm wrong in this interpretation, because it would be a disgusting and cynical way of using primary legislation. I'm sure that all would agree that the Government and Parliament ought to only introduce legislation that they genuinely intended to become law.