Now that they have renewed the connection to the Bakerloo line at Embankment, I spend more time walking down Piccadilly.   My eye is often caught by the grandiosity of the former headquarters of the Royal Institute of Painters in Watercolours, which opened in 1883, having been founded as the New Society of Painters in Water Colours in 1831 (after a false start in 1807) as a protest at the refusal of the Royal Academy to accept watercolour as a legitimate medium.   Their exhibitions were originally held at 16, Old Bond Street, then moved to Exeter Hall in the Strand (the site of the Strand Palace Hotel).   In 1838, they moved to 53, Pall Mall and in 1883 to Piccadilly, to a building designed by E.R. Robson and including on the façade heroic busts of the greatest watercolourists:-  SANDBY, COZENS, GIRTIN, TURNER, D. COX, DE WINT, BARRET and W. HUNT:-