An article on "artist and raconteur" Willy Feilding provides an explanation of his last name:
For Feilding, whose unusual surname is due to the fact, he says, that his parents misspelt it on his birth certificate, is not merely a painter and bon viveur.The name "Feilding" isn't that unusual. Willy's relatives, the Earls of Denbigh, have used that spelling since the title was created in 1622.
The bohemian 66-year-old, a cousin of the Earl of Denbigh, has been a friend and companion to some of the world's most colourful celebrities, from the moustachioed madness that was Salvador Dali to that peerless beauty Princess Grace of Monaco. [Link]