I remember when I was serving early on we had one pilot (whose name escapes me although I can see him clearly) who thought he was the last Warrant Officer pilot to be "forced" to take a commission. He had flown Lancasters and been on Maritime surveillance after the war. He was pretty upset at the initial pay drop. One of our best pilots though.
On another note, wasn't there a sleeve badge - a copper-bronze eagle with a crown above (quite small) that was worn by the Commissioned Warrant Officers?