Helen Dunmore and M. P. Shiel are not both of West Indian descent.
Helen Dunmore FRSL (12 December 1952  5 June 2017) was a British poet, novelist and children's writer. 
Matthew Phipps Shiell (21 July 1865  17 February 1947)  known as M. P. Shiel  was a prolific British writer of West Indian descent. 
