It's not pronounced 'Fanshaw' now, though popularly believed to be so. Feston-hew, Feston-haw, or even Feather-stun-haw perhaps, but not Fanshaw.
The really deceptive one is Powell. Is it Anthony POW-el for the author, and Baden PO-el for the scout leader, or the other way round, or some other arrangement?
Woburn Abey ? Is that Woe-burn, Woe-bun, Wooburn, Woo-bun or some other pronunciation ? Even the Dukes of Bedford couldn't agree. The present one says Woe-burn. The previous one seemed to settle for Woo-bun, but his immediate descendant settled for what most people say.
And Gumster for Godmanchester and Stew- key for Stiffkey are two examples of how locals pronounced the place names many years ago but which have since become pronounced as they look.