(1) A document shall be an approved combined policy and guarantee within the meaning of this Act if, but only if, it complies with all the following conditions, that is to say: -
(a) it is issued to a person (in this Act referred to as the insured) named therein; and
(b) it complies with all the conditions required by this Act to be complied with by an approved policy of insurance save that the insurance thereby effected does not extend to the whole of the sums required by such conditions to be covered by such insurance; and
(c) the payment by the insured of so much of the said sums as is not covered by such insurance is thereby guaranteed by the vehicle insurer by whom such document is issued; and
(d) such document in so far as it relates to such guarantee complies with all the conditions required by this Act to be complied with by an approved guarantee.
(2) A document which complies with all the conditions set forth in the foregoing sub-section of this section shall not be preve