See https://www.assemblytestimony.org/
In January 1967, Arthur Maurice Salway Gooding (1915-1999), the cousin of the late Dr. David Willoughby Gooding (1925-2019) from Belfast, took over the editorship of the Assembly Testimony; see here: https://assemblytestimony.org/?q=node/478#TRIBUTE
Clifford the magazines can be accessed at assemblytestimony.org They have monthly issues from 1952-2020 and also book/booklets that they have published!