TRT,
I pressume you are referring to the collar badge as worn by the 16th City of Cardiff Battn and not the Cardiff Pals which were the 11th Battn and did not wear a unit specific badge except for the cardboard one used prior to issue of uniforms.
The link below will to you to the post for the 16th collars.
Hwyl,
Kevin
http://www.britishbadgeforum.com/for...4&postcount=10