The Marquess of Westminster drinking fountain

It probably sounds like the name of a pub, but in Pimlico is a drinking fountain erected to the memory of the 2nd Marquess of Westminster.Richard Grosvenor, 2nd Marquess of Westminster was a landowner and later politician, and father of the first Duke of Westminster, a title that still exists and is held by the 7th Duke.
Now, memorial fountains are not that unusual in London, but what makes this one stand out a bit are the mosaic panels on all four sides of the fountain. On one side it says In m