GB 1877 SG147 Pl.15 Cover - London to Punta Arenas, Costa Rica

1877 Overseas Mail. Very fine cover from London to Punta Arenas, Costa Rica carried by Royal Mail steamer 'Via Southampton'. Prepaid at the 1s per ¬Ωoz rate by two 6d grey Pl.15, one at the top right cancelled by a lightly struck London 'L2' duplex for AU.16.1877 this was deemed unsatisfactory so the stamp was additionally cancelled by black manuscript and blue crayon. The second stamp at lower right has been left completely uncancelled. With no evidence that any late fee payment was due or paid suggests that this postmark may have been applied in error hence the indecision. The cover was carried by RMSP steamer 'Moselle' which departed Southampton on the 18th. A very unusual and scarce destination item. - P223012037