Thanks as usual, Wikimedia Commons
In 1844, Carl Timoleon von Neff (Baltic Germany, 1804/5? - 1876) painted this portrait of a striking young woman holding her little dog. All I can find of her is the title: Lady Barrett of Belhus. While I didn't find many of the answers I sought, I did find some other curious things that led me to reflect on struggle, position and transience. I'll tell you why.
Carl Timoleon von Neff was a court painter to Tsar Nicholas I of Russia, a position he achieved by a great deal of hard work and applied likeability, for he was the illegitimate child of a French governess. He is identified as being Baltic German, from Estonia, born at the "Pyssi manor," and died in St. Petersburg. He did well enough to own a manor house at Muuga in Estonia (a Flickr group of the house here).
Last but not least, he traveled to Britain at one point, for the young lady in the painting belonged to a family of minor nobility in Thurrock, county of Essex. The Belhus family's country house was demolished in 1957, and the family's history was mildly checkered. It is possible that this young woman is either the wife or the daughter (I think the latter) of Sir Thomas Barrett-Lennard, 1st Baronet.