I've updated the page for Richard Gibson and added him as another Great War fatality. Chailey Parish Magazine doesn't have an awful lot to say about him. He's mentioned as serving his King and Country in 1914 but by December 1916 he disappears altogether.
Whilst I can't be sure, I feel fairly confident that this man is the same Richard William Gibson who lost his life in September 1916 whilst serving with the 2nd Royal Sussex Regiment. He was a regular soldier (enlisting circa 1904) and an Old Contemptible, having arrived in France at the end of August 1914.
Richard has no known grave and is commemorated on the Thiepval Memorial on the Somme. His name does not appear on the Chailey War Memorial or on the memorial at Hailsham where he was born.