"(4) On an appeal under section 82(1) or 83(2) against a decision an adjudicator may consider evidence about any matter which he thinks relevant to the substance of the decision, including evidence which concerns a matter arising after the date of the decision. (5) But in relation to an appeal under section 82(1) against refusal of entry clearance or refusal of a certificate of entitlement under section 10 – (a) sub-section (4) shall not apply, and (b) the adjudicator may consider only the circumstances appertaining at the time of the decision to refuse."