I found S J Dark's notice in the Gazette for his commission into the RASC in 1947 as a 2nd Lt from a cadet and again in 49 and he seems to have served with them throughout his career, whilst Lewis started with the RWF but later served with the Cadet Force.
https://www.thegazette.co.uk/London/...upplement/2175
https://www.thegazette.co.uk/London/...upplement/5829