Had a word with my friend re the RAAF crowns (as he is much more knoledgible on the RAAF front than me) and he says, '...The embroidered crowns like the W/T sleeve badges were I believe, adopted for aircrew which was brought about by complaints of 'Foreign Object Damage' (FOD), which meant that in the confined space of aircraft, the metal badges tended to catch on objects and tore or damaged uniforms, hence the embroidered types were developed, and later in the war adopted by ground personnel...'
This seems to ring a bell as a conversation i'd had with him before, but anyway, there are also some official reference numbers for the badges, so in the RAAF at least they were official issue. RAF wise I've yet to find anything...