Great Britain 1920 Postage due, SGD6.
Very fine cover from Australia endorsed "Via Mantua" bearing a ½d green & 1½d deep red-brown (SG20+59), cancelled by Katoomba N.S.W. circular date stamps for DE.3.1920. Addressed to Folkestone and deemed underpaid with a "4d I.S." handstamp, the charge collected by a 4d dull grey-green postage due cancelled by a Folkestone circular date stamp for JA.11.1921.
A scarce and interesting piece of postal history.
