I think the pseudonym also had something to do with a different music publisher than those on the album where Mr. Fury was listed as the writer as was.
It was somewhat common in the U.S. for some writers to use assumed names, chiefly if, say, they were a BMI member but what they wrote or co-wrote was published by an ASCAP-affiliated concern. Another factor in using pseudonyms was, especially in the case with some R&B acts, for tax purposes (namely James Brown on many later '70's records including "Get Up Offa That Thing," and Joe Tex on "Ain't Gonna Bump No More (With No Big Fat Woman)" which he had an aunt credited as co-writer with his producer Buddy Killen, though Mr. Tex did co-write that one himself).
"wilbur wilberforce", credited with writing six of the ten songs, was billy fury; he invented the pseudonym because he "didn't want to seem big-headed". (eye-, or perhaps "ear-" witness, speaking in "the sound of fury" documentary programme on billy fury's life and music.)