I think there is a strong possibility that proto-Celtic people came from SE Asia. Read the book.
"In Eden in the East Stephen Oppenheimer puts forward the astonishing argument that here in Southeast Asia was the cradle of civilisation that fertilised the great cultures of China, India, Mesopotamia, Egypt and Crete six thousand years ago."
Do you have you Oppenheimers mixed up? Certainly the Celts were long before this canoe, though.