Bidspirit auction | British Commonwealth -Aden Protectorate States

British Commonwealth -Aden Protectorate States - Kathiri State of Seiyun - 1966, Sultan Hussein, trial black instead of blue bilingual surcharge 5fi on 5c brown, right sheet margin block of four, full OG, NH, VF, a copy of A. Rendon certificate for complete sheet of 100, this block has positions 69-70/79- 80, SG mentions this black surcharge, but not lists the price, Mi #55b, €600++, SG #55 var