How to Solve a Problem Like Brexit (no cats)

Im briefly reviving Pangloss to publicise something I think important that just came out  as  a broad hint from the Research briefing team at the House of Lords.

This just came out: http://researchbriefings.parliament.uk/ResearchBriefing/Summary/LLN-2016-0034

It contains the usual stuff about art 50 (no one knows if Parl has to agree or not, or if it falls with the PM's prerogative) but then..

"Parliament would have a statutory role in ratifying an eventual withdrawal agreement and any other international agreements arising from the negotiations if they were subject to the usual procedure for ratifying treaties. The House of Commons potentially has the power to block the ratification of a treaty indefinitely;the House of Lords does not. Under the terms of Article 50, the UK’s membership would cease two years after it gave formal notification of its intention to leave, if no withdrawal agreement had come into force by that point, although the two-year period could be extended on the unanimous agreement of all EU member states."

In other words, Gove (say) could call art 50, negotiate EEA or something else and then find Parl would not pass it.

The EU wouldn't care (or might not anyway - we'd be out) : but it would cause chaos here. Any attempts to stay in the Single market would fail.

This HAS to be a "golden rule" argt to interpret art 50 the Pannick way ie Parl having to say yes before an art 50 notification is given. If a provision interpreted literally does not make sense in UK law  - as here, allowing the PM to start something which he would be incapable of finishing - then it has to be interpreted in a more purposive way.

ie in a way that respects existing law on division of power between Parl and PM. And then we re introduce Pannick's ev that there is a basic rule the preorgative should not be used to disempower established Parliamentary competence. Only this time it is non controversial as no one can argue Parl does NOT have the prior and established right to ratify a treaty even if PM has negotiated it.

Any thoughts?