1. The authorities of a Member State may approve persons who have obtained all or part of their qualifications in another State provided they fulfil the following two conditions:
(a) the competent authorities must consider their qualifications equivalent to those required under the law of that Member State in accordance with this Directive; and
(b) they must have furnished proof of the legal knowledge required in that Member State for purposes of the statutory auditing of the documents referred to in Article 1(1). The authorities of that Member State need not, however, require such proof where they consider legal knowledge obtained in another State sufficient.