The items used in the Trials, of what would become Patt. ’58 W.E., had a separate sequence of codes, pre-fixed EXPN. From the existence of items coded EXPN / No. 2, there was evidently a No. 1 set also. It is not known if there were sets beyond No. 2. Few of these codes have been noted, so they are not included here. The No. 2 Set components differed from 1st Issue Patt. ’58 only in having a press fastener on every QR fastener. This was located under the flexible pull tab and prevented accidental pulling of the QR securing tab.

In large part, the old code sequences of V.A.O.S. Section A1 remained un-changed, when transferred to C.C.N. Section CN in 1951. The V.A.O.S. was divided up into alphabetic blocks, which meant the codes for Patts. ’08 and ’37 W.E. were widely dispersed. The transfer of Patt. ’44 W.E. from Section A6 to A1 saw the first instance of a sequential code allocation. Patt. ’58 W.E. followed suit, but in so doing, three old A1 codes were re-used: A1/AA 0030, A1/AA 0031 and A1/AA 0032 were given a rare second outing as CN 0030 – 0032. This was only possible as these codes were Musical Instruments, once P.V.O.S. Section 1b, later V.A.O.S. Section A1 where they now remained, Section A1 being re-named Musical Instruments.

When the N.A.T.O. coding system was applied, several components had already been modified. For the sake of convenience, these and subsequent changes are referred to as “Issue 2”, etc, though these designations were not used by the Army. The switch to NSN codes generally was not at one point in time, the earliest occurrence being 1958 (in an R.A.F. listing). In 1965, large sections of C.C.N. Section CN still had not been converted, although Patt. ’58 had been, from around 1963.