I believe these are the cockade side pieces with Queen Adelaide's brooch in the centre of a tighter configuration of the three - plus Cullinan III as a drop. It's really very effective.
But I'm open to other suggestions.
--Previous Message-- : I believe the two large side pieces are the : sides of the cockade, with drops added. : Queen Mary often wore them with something : else in the centre. : In this instance the centre is probably : Queen Adelaide's Brooch (which Field called : the William IV). : : Below, this official portrait (not the : coronation) shows the entire cockade in the : V arrangement. : Queen Alexandra wore the three-piece : cockade.