5.— (1) For the purposes of this Act a product is defective if it fails to provide the safety which a person is entitled to expect, taking all circumstances into account, including—

( a) the presentation of the product,

( b) the use to which it could reasonably be expected that the product would be put, and

( c) the time when the product was put into circulation.

(2) A product shall not be considered defective for the sole reason that a better product is subsequently put into circulation.