Error of law: meaning of error of law, and effect of costs award

In Martin v Harris [2019] EWHC 1962 (Ch) and Martin v Harris (No 2) [2019] EWHC 2735 (Ch), Michael Green QC discussed two important questions relating to appeals on points of law under section 69 of the Arbitration Act 1996: what is an error of law, and if an award is set aside what is the fate of the costs award relating to the substantive award?

Martin v Harris : the facts