These “spaniels” were owned by Mrs. Orby Hunter and were painted by Ben Marshall.
Their names were “Diver” and “Shuckleback.”
Diver is a barbet/English rough water dog/poodle type of water dog, but Shuckleback looks like a proto-curly coated retriever.
Maybe a bit of St. John’s water dog had been crossed in, or maybe he was of a sort of water dog that is part of the St. John’s water dog’s ancestry.
I imagine the Tweed water dogs being very similar to Shuckleback, just of the yellow or reddish coloration.