16. A person who is not an authorised person does not carry on an activity of the kind specified by article 14 by entering into a transaction relating to a contractually based investment—
(a)with or through an authorised person, or an exempt person acting in the course of a business comprising a regulated activity in relation to which he is exempt; or
(b)through an office outside the United Kingdom maintained by a party to the transaction, and with or through a person whose head office is situated outside the United Kingdom and whose ordinary business involves him in carrying on activities of the kind specified by any of articles 14, 21, 25, 37, 40, 45, 51, 52 and 53 or, so far as relevant to any of those articles, article 64 (or would do so apart from any exclusion from any of those articles made by this Order).