Complex sentence: A College Stamp was issued in the 1960/70's to prepay a local delivery of mail by the college Porters, it was shortlived and only a few of the stamps exist, one known on cover.
Split into simpler sentences: A College Stamp was issued in the 1960/70's to prepay a loacl delivery of mail undertaken by the porters. It was shortlived and only a few of the stamps exist, one known on cover.