Under the UK Construction Act payment regime, a paying party that intends to pay less than the sum notified must issue a valid pay less notice within the contractual deadline, setting out the sum it considers due and the basis of its calculation.
Miss the notice, or issue a defective one, and the notified sum becomes payable regardless of the merits: the foundation of smash-and-grab adjudications.
The regime rewards administrative discipline on both sides: applications and notices that are on time, properly calculated and properly served, with records to prove service.