What is the test for "convenience" when a plaintiff seeks trial by jury in an action that involves a scientific investigation?

While the trial of an action with a jury that involves a scientific investigation may not be the most convenient mode of trial, that is not enough to displace the right of the litigant who seeks trial by jury. In Mewhort v. Frimer (1980), 19 C.PC. 59, McEachern C.J.S.C., as he then was, said that: … "convenience" in the context of … Rule [39(27)] … relates to the proper conduct of the trial, including an understanding of the issues and evidence, the submissions of counsel, and the Judge's charge. He also observed the following: [When] the case involves a prolonged examination of documents … or a scientific, or a local investigation, then the [trial] Judge must consider not only the issues and the nature of the evidence and exhibits, but also whether the examination or investigation may conveniently be made with a jury. On the other hand, if the issues are intricate or complex then the [trial] Judge may, in the proper exercise of his discretion, order that the trial proceed without a jury, and convenience [in that case] need not necessarily be a factor.