Amazon: "Our records still show we haven’t received valid tax identification information for your account. In order for Amazon to comply with U.S. tax reporting guidelines, you must complete our short online tax interview by 10/25/2013 to avoid your books being removed from sale on Amazon."
WH: 'I am not obliged to conform to "U.S. tax reporting guidelines". When Amazon pays its fair share of U.K. tax I might consider it. Until then you can get stuffed.'
Update (September 2014): I relented and filled in the form.