"It is not a question of [the Adjudicator's] deferring to the Secretary of State's judgment of proportionality in the individual case. The Adjudicator's decision of the question whether the case is truly exceptional is entirely his own. He does defer to the rules; for this approach recognises that the balance struck by the rules will generally dispose of proportionality issues arising under Article 8; but they are not exhaustive of all cases. There will be a residue of truly exceptional instances. In our respectful view such an approach is also reflected in Lord Bingham's words in Razgar , which we have already cited: 'Decisions taken pursuant to the lawful operation of immigration control will be proportionate in all save a small minority of exceptional cases, identifiable only on a case-by-case basis'."