Posted 25 October 2005
NO...you cannot purchase the CARTE ORANGE transportation pass anywhere other than at a RER or Metro station in or around Paris. What you probably can purchases are PARIS VISITÉm consecutive day transportation passes at Waterloo International....but I'd bet that their price was inflated by a third-party agent selling them. The regular '..official..' price at any Paris Metro station (your arrival terminal, GARE du NORD in Paris as an example) will probably be a few €uro less.
So DO NOT pre-purcahse a PARIS VISITÉ pass in London...and spend the money you save on a better bottle of wine with lunch or a second dessert with dinner.