UK law is weird. Technically they're right. In UK rape is defined as:
(1) A person (A) commits an offence if—
(a) he intentionally penetrates the vagina, anus or mouth of another person (B) with his penis,
(b) B does not consent to the penetration, and
(c) A does not reasonably believe that B consents.
But as it is worded, especially the first top comment, it reads like defining rape.