I thought chartreux is recognised by TICA... perhaps get in touch with them to see if they can put you in contact with any uk breeders. If there are none in the uk, then perhaps they can help you find a breeder to import your kitten from.
edit to say this is one of the international cat clubs. An email to these guys might give you an idea if there are any registered in the uk.
http://chartreux.cat.free.fr/contacter.html