Thanks to moddsey for alerting me to this 1929 ad in the Hong Kong Telegraph for my family's company. It chimes in with the 1912 one uploaded by IDJ titled "monumentalists." I'm still not sure if the monumental masonry yard and the tile factory were at the same address. According to Jason Wordie's article, C.E. Warren & Co plaques on gravestones in countries outside Hong Kong are simply marked "Causeway Bay".