(1)Where—
(a)a defined authority (as a bidding authority) entered into a works contract before 1st April 1989 (and whether or not before the passing of this Act), and
(b)had they entered into the contract on 1st April 1989 they would have infringed section 4 above,
on that date the parties to the contract shall cease to have power to carry it out.
(2)If the contract is governed by English law and the parties to it do not make other provision before 1st April 1989, the [1943 c. 40.] Law Reform (Frustrated Contracts) Act 1943 shall apply to the contract with effect from that date.