ReMed Ltd (RM) is a manufacturer and distributor of natural and herbal remedies operating in the United States. The Melbourne Apothecary Ltd (MA) is a Melbourne distributor of health supplements and natural remedies. In January 2021, MA ordered 3,000 boxes of Inner Glow Powders, a new natural remedy to boost the immune system, from RM. The powders have taken the US market, and MA believes they will be equally successful in Australia. The sale is agreed on FCA (Los Angeles) for delivery between 1 February and 20 June 2021. MA and RM agree that payment will made via a commercial, irrevocable letter of credit.

In early February 2021, RM informed MA that the product was ready for delivery. In accordance with the contract of sale, MA obtained a letter of credit from National Wealth Bank (NWB) and the Bank of Los Angeles (BLA) is named as the advising bank. The letter of credit specified that it incorporated the UCP600 rules and that presentation must be 'made within 15 calendar days of the shipment or before 21 June 2021, which is when the credit expires'.

After receiving notification from BLA that the credit is available, RM organises shipment of the goods with Los Angeles Airways (LAA). On receipt of the goods from RM on 10 June, LAA issued an Air Waybill which details that the goods would be carried from Los Angeles to London on an LAA flight and London to Kuala Lumpur and then on to Melbourne on a Qantas flight. The Air Waybill recorded the weight of the consignment as 450kg.

On receipt of the goods on 17 June MA discovers several issues with the powders. The powders are incredibly sensitive to moisture and, while RM packed the goods with care and as advised by LAA, it appears that moisture somehow contaminated the cargo. The most likely explanation for the moisture's presence is that the cargo-hold temperature on the flight from Los Angeles to London was not properly regulated. Alternatively, the moisture may have contaminated the cargo whilst being stored in LAA's warehouse. A large storm had struck LA during this time, and some water leaking into the storage facility had been observed.

As a result, damage to the powders has occurred. In some boxes the powders have solidified. In other boxes that were exposed to more moisture, the powders have dissolved and been lost entirely. With all that remains being some residue at the bottom of the boxes. As a result, MA has suffered losses, inclusive of loss of profits, to be $40,000.

After having inspected the boxes to determine which powders remain merchantable, on 8 July MA contacts Qantas to complain about the damage.

Pursuant to an arbitration clause included in the contract of carriage, MA and the carriers Los Angeles Airways (LAA) and Qantas agree to submit their dispute to the Singapore International Arbitration Centre. The arbitration proceedings are to be conducted by a sole arbitrator, under the UNCITRAL Model Law. The Airlines and MA agree to the appointment of Mr James Last, a former lawyer from the UK, who recently began working as an arbitrator in Singapore. The arbitration has been set to run for five days.

On day three of the arbitration, MA learnt that Mr Last, who had been quite hostile to one of MA's expert witnesses during the proceedings, had appeared as a witness for Qantas in three different arbitration proceedings in the last 10 years.

Discuss how and on what grounds MA might challenge Mr Last's appointment at this stage of the proceedings?