A supplier who in trade or commerce is a party to a contract shall not —
(a) when he or she is in breach of contract, exclude or restrict his or her liability in respect of the breach; or
(b) claim to be entitled to render —
(i) a contractual performance substantially different from that which was reasonably expected of him or her, or
(ii) no performance in respect of the whole or any part of his or her contractual obligation,
except in so far as the contract term satisfies the requirement of reasonableness under section 167.