IP98 Diss Postcode district IP98: 1 named streets and 7 live postcodes, in South Norfolk. Streets Market Hill, Diss Postcodes IP98 1ER IP98 1HH IP98 1NP IP98 1PG IP98 1RT IP98 1XY IP98 9RA Source: ONS Postcode Directory (live postcodes only) and OS Open Linked Identifiers for the streets.