Fr. Roger's period as Headmaster lasted from 1961 to 1969. During this time there was a notable increase in the standard of teaching, academic achievement, activities and clubs. New tennis courts were built in 1963. Biology was introduced to the curriculum in 1962 and 1967 saw the creation of a new art department, which was later to have a deep impact on the school.
Fr. Roger himself raised the standard of school drama to an altogether new and almost professional level. It was typical that at the time of his resignation in 1969 he should leave behind him a trail of projects, not least of which was a ready plan for the next major phase in the school building programme. This consisted chiefly of an extended classroom block which was erected under his successor five years later, and a new House, already built, for a small number of sixth form girls, later to be known as Hedley House.

The task facing Dom Mark Jabalé, who succeeded Fr. Roger was predictably not an easy one. However, such was the tradition established by Fr. Roger that the school rode the change with the minimum of difficulty. During his relatively long period as Headmaster Fr. Mark succeeded in further raising academic standards. To sports, notably rugby and rowing, he gave such encouragement as to have lifted them to levels never before attained. Whilst the conversion of the sound floor of the 1931 building to a new cafeteria refectory was largely completed under his predecessor, Fr. Mark saw the reconstruction of the old pig farm into an efficient and picturesque art and crafts block and finally executed Fr. Roger's plan for the extension of the teaching facilities of the Martin Building.
Other valuable amenities were added during his time. The squash courts were principally donated by the Belmont Association (Old Boys) and the swimming pool was donated by a parent and some generous friends. The middle and top floors of the Siberia wing were converted into an infirmary and guest quarters respectively and the old Cantilupe dormitory was converted into an increased quarter for girls and a flat for the House Mistress.
A major enterprise in Fr. Mark's Headmastership was his establishment of a new House for day pupils. Housed in the now converted wooden classroom of 1957, the thirty-three boys of the new Ethelbert House quickly began to make their impact throughout the school. However in 1978 Hedley House closed, bringing to an end a 10 year period during which some seventy to eighty girls had done their sixth-form at Belmont, and brought a different dimension to the school. Successively Miss Florence Boxford, Miss Gill Midgley, Mrs Pauline King and Mrs Patricia Camden-Smith had served as Housemistresses.
When Fr Mark retired as headmaster in 1983 Fr Simon McGurk became the fourth old boy to hold the post. He became Headmaster at a difficult time and had a hand in the regrettable decision to close Llanarth, and establish instead a junior house at Belmont, Benet. This necessitated the loss of one of the school houses - Kindersley. However, he brought a progressive vision to the school, with much enthusiasm and dedication.