What is the test for determining whether a written contract is a question of law?

In addition, Apache points to this quote from Lord Diplock in Pioneer Shipping v. BTP Tioxide, [1981] 2 All E.R. 1030 at 1035: The answer must depend on the true construction of the agreement between the parties; and in English jurisprudence, as a legacy of the system of trial by juries who might not all be literate, the construction of a written agreement, even between private parties, became classified as a question of law. ... A lawyer nurtured in a jurisdiction that did not owe its origin to the common law of England would not regard it as a question of law at all. ... Nevertheless, despite the disappearance of juries, literate or illiterate, in civil cases in England, it is far too late to change the technical classification of the ascertainment of the meaning of a written contract between private parties as being ‘a question of law’ for the purposes of judicial review of awards of arbitrators or decisions of administrative tribunals from which an appeal to a court of justice is restricted by statute to an appeal on a question of law.