On November 29th 1968 Fr. Thomas O'Sullivan took up his duties as Parish Priest at St. Bernard's. Fr. Deeney remained as curate. Fr. O'Sullivan was a quiet unassuming man who had a wonderful rapport with all his parishioners. He was deeply interested in the spiritual well-being of the youth of the parish. A rambling club was formed. The cellars of the house - Shawbrook Lodge - were converted into a meeting place for the youth club. He introduced liturgical changes as recommended by Vatican II. Fr. O'Sullivan pressed the Diocese and the Department of Education for an extension to be built to St. Bernard's School. Permission was granted in February 1970 and the new infant block was blessed and opened by Fr. O'Sullivan in October 1971.
In March 1972 Fr. Deeney was appointed Parish Priest of St. Mary's, Burnley and soon afterwards Fr. O'Sullivan was taken ill with diabetes. He found the task of running a large and busy parish too much, and in September 1972 Fr. O'Sullivan exchanged parishes with Fr. Tangney. He moved to the rural parish of St. Peter's and Paul's Barrowford. He died there on February 10th 1980 aged 56.