It appears from
photos that the Union Flags were replaced late 1904 early 1905.
Although a new pattern appears in the 1913 Flag Signal Book, photographs
show that only the 1908 pattern was being worn up to the start of
World War 1. ( HMS King George V was wearing
the 1908 pattern during a visit to Kiel in July 1914 ).
were some slight variations to the pattern in some photos possibly
due to the unavailability of certain flags on those ships. I have
not located information as to whether there was a change from the
1908 to the 1913 pattern during WW1.
The Red & Green Flags, later to become Port and Starboard Flags, ( See 1919-1948 page), appear to have been introduced in 1909. They are not on the 1908 Flag Card but the Port Flag was flown by HMS Inflexible at the Hudson-Fulton Celebrations in New York in October 1909.