It seems the Craighead family were tailors in New Zealand for several generations. Hugh Clark, Edwin George and his brother William Bruce Craighead were tailors and outfitters in Ashburton on the South Island. It appears W.B moved to Wellington and continued as a tailor. Huia Bruce Craighead was born in Wellington in 1897 so presumably was his son. H.B. would also become a tailor and from around 1932 traded as H.B. Craighead Ltd. The New Zealand Railways button shown below is backmarked H.B.Craighead Ltd. Wellington.
And back across the Tasman, I now have several more examples of a given design of Embassy branded buttons. As you can see, this style was available in at least 3 colours and sizes!