Hi, could the five be a 'S', the carlton serial number is usually prefixed with a letter up to the late sixties, between 1968 and 1972 it all goes a bit fuzzy : -
A 1939 F 1957-58 L 1963
B 1940-48 G 1959 M 1964
C 1948-52 H 1960 S 1965
D 1953-54 J 1961 T 1966
E 1955-56 K 1962 Y 1967
Terry