As far as the law goes, whether there is a disclaimer is irrelevant; the law states:
A person commits an offence who with a view to gain for himself or another, or with intent to cause loss to another, and without the consent of the proprietor—
(a)applies to goods or their packaging a sign identical to, or likely to be mistaken for, a registered trade mark, or
(b)sells or lets for hire, offers or exposes for sale or hire or distributes goods which bear, or the packaging of which bears, such a sign, or
(c)has in his possession, custody or control in the course of a business any such goods with a view to the doing of anything, by himself or another, which would be an offence under paragraph (b).
It doesn't matter whether they presented it as the genuine article or not; the simple fact that it carries a trademarked logo is what the law covers.
The penalty is:
A person guilty of an offence under this section is liable—
(a)on summary conviction to imprisonment for a term not exceeding six months or a fine not exceeding the statutory maximum, or both;
(b)on conviction on indictment to a fine or imprisonment for a term not exceeding ten years, or both.
Constantly challenging for an instance where a person has sought to sell an item pretending that it was something else is a red herring (oh lawd - another fish!); the issue is in selling the item itself.