Falkland Islands Dependencies SG Z143 1928 registered cover from South Shetlands to England with 1921-28 2d

South Shetlands. 1928 (NO 4) registered cover to England, franked by 1921-28 2d deep purple-brown, tied by 'SOUTH SHETLANDS' cds with 'SOUTH GEORGIA' registration label at upper left. Plymouth registered oval transit (18 DE) backstamps. Minor toning but an unusual usage, underfranked by 2d (the correct rate being 4d = 1d postage + 3d registration) but apparently accepted without surcharge. [N.B. Registration facilities were not available in the South Shetlands. Letters and parcels requiring registration were forwarded to Port Stanley or South Georgia (whichever was first port of call) where registration could take place.] - P267000744