Royal Fusiliers (London) Collar / Cap?
 

Added this to the collection. I feel certain it was intended to be a collar badge. Were these, however, documented as having been used as cap badges? Being the same size, it would seem likely.

They are not "documented" per se as used for cap badges, but they most certainly were used in many circumstances wherein expediency due to lack of availability necessitated their use as cap badges.

CB