It's worth throwing into the mix that our green chums tend to want to keep technical expertise in the ranks, while the response in the dark and light blue is to commission those who show some nous and ability coupled with confidence.
A quick look at the numbers going through BRNC, RMAS and Cranwell with former ranker service will show that the Army has a very different take on the usefulness of former service in the ranks among the officers. They do tend to catch up with some in their later NCO service, but quite late, which limits their promotion prospects.