1D ARCHER PL.100 EXPERIMENTAL PERFORATION HORIZONTAL PAIR (GH) (GI) (SG16b)/USED SOUTH PETHERTON (SOMERSET). 1850 1d Archer pl.100 fine used horizontal pair lettered GH GI, cancelled several strikes of the "725" numeral of South Petherton (Somerset) and clearly showing Alphabet check letters. Lettering GI MISSING FROM IMPRIMATUR SHEET and GH "H VERY MISPLACED". Unusual to find as a pair. (Ref 100534).