On Nellie's view of the Regal Circlet, the right-hand floral spray seems to have a clip-like device at the narrow part of the spray, which doesn't seem to have an equivalent on its opposite left-hand side floral spray.
The base of the floral spray, where it attaches to the band, appears as if it could be removable (slipping in and out of those little round pin-like thingies).
Could it be that the floral spray(s) were originally designed to be removable and perhaps worn as brooches?
The cross-pate, on the other hand, appears to be solidly and permanently affixed (it seems to be nailed and soldered on).