The Explosion Of British Society Childbirth Without Fear The Pan Book Of Opera
PAN XP2 from 1963 PAN MP3 from 1963 PAN T55 from 1964

The P in the code stood for PIPER and the initial letter for the price.
X was 3/6, M was 5/-, T was 6/-, E was 7/6, H was 12/6 and Z was 15/-