12.—(1) Where the contract is with two or more individuals practising in partnership, the contract shall be treated as made with the partnership as it is from time to time constituted, and the contract shall make specific provision to this effect.
(2) Where the contract is with two or more individuals practising in partnership, the contractor must be required by the terms of the contract to ensure that any person who becomes a member of the partnership after the contract has come into force is bound automatically by the contract whether by virtue of a partnership deed or otherwise.