Hello Graham,
If you look at the TCC bulletin 24#2 I wrote an article about the house family. I have several pieces with the same house; creamer, sugar w/o lid, C&S, and a jug. Yet to find one with a mark. Often times you will see them referred to as Portobello Ware, but I believe most are made in Staffordshire. The biggest majority are un-marked.
Sincerely,
Jewell