Marking on Pair of Silver Albert Links

Have i pair of , i believe & stand to be corrected vintage era albert clips , both marked 925 & both marked in a shallow cartouche shaped similar to a clover leaf with initials i think are I B B , maybe a sponsor mark. I would like to try
& clarify this mark.

IBB is International Bullion & Metal Brokers. They registered marks at both Sheffield and London assay offices.


Thanks so very much again Phil for your help on my seemingly endless silver questions