Failure to set aside an arbitral award on the basis of a novated expired contract (BXH v BXI)

Arbitration analysis: What happens to an arbitration clause upon the expiration of the main agreement and where parties continued to perform the contract as if it had not expired? What is the Singapore court's approach where the main contract contains both an arbitration clause and a court jurisdiction clause? Can the appointment of a sole arbitrator in accordance with the arbitration agreement be contrary to the same provision providing for a three person tribunal?