95. Where a person responsible for putting a controlled product into circulation is charged with an offence under these Regulations, in respect of a controlled product that has been manufactured or assembled to his order by another person, and which has been so manufactured or assembled so as not to comply with his order, it shall be a defence for him to prove—
(a)that, in placing his order, a copy of the documents relating to the specifications for manufacture and assembly of the product were available, or had been provided, to that other person and that the person responsible for putting the product into circulation had instructed that other person to manufacture or assemble the product in accordance with those specifications,
(b)that if that other person had complied with that instruction, no offence would have been committed, and
(c)that the person responsible for putting the product into circulation did not know, and could not with the exercise of reasonable care have known, that that instruction had not been complied with.