Yep they changed their GRE requirements after the application window opened. If you have few mathematics modules in your background, I'd recommend taking it - the admissions tutor was worried about my maths background even coming from a 4 year engineering course at Imperial and scoring highly in the maths part of the GRE (albeit this is for the specialist course).
And for those wondering, by that definition, as far as I can tell the specialist courses DO require the GRE.