They really look to me like Holger Eriksson sculpts, particularly the horses. I have a mounted Sikh officer, which is an Eriksson casting, and the horse is virtually identical. But I don't recall that any form of Eriksson's work had "ER" inscribed under the bases. His work either had, "SAE", "HE" (as a conjoined monogram), or "EIRE", for the castings produced in Ireland. I have a copy of "The Toy Soldier Artistry of Holger Eriksson" by Lou Sandbote, Norman Joplin, and Philip Dean. I'm looking through it now, to see if I can find any info about it. But tentatively, I think these are Eriksson castings.
Prost!
Brad