Construction contract – Adjudication – Enforcement – Adjudicator's jurisdiction. Court of Session: In an action in which the pursuer sought to enforce an adjudicator's decision increasing the sum the defender was liable to pay it in respect of a payment certificate, the court reduced the adjudicator's decision ope exceptionis, holding that he had failed to exhaust his jurisdiction by failing to address a material defence, namely set off of delay damages, which the defender was entitled to state.