The title contains Paul's service number, 81457397BG. The first two digits are the year in which he was registered for National Service. This should have happened in the year he turned 16. If he was 18 in 1982 he would have registered in 1980 so his service number should have start with 80, not 82. If he was only registered in 1981, he would not have received call up papers for the January intake.