ok, let me explain.
those with the capbadge under command of 7th bde are under 7th
bde.
these include the guardsmen, and the other vocationalists. an
unconverted medic is only infantry trained, hence, the
qualification to wear the infantry beret. since guards is
essentially an infantry vocation. almost everyone pass out frm bmt
is infantry trained at the least.
for the blue beret, can only conclude that there are support arms
units under 7th. afaik, don't remember 7th has support arms when i
was there. hm.. even mt line also wear green beret.