A little sleuthing revealed that the recipe I was given was perhaps from, or inspired by, the Ginger Crunch recipe from a cookbook produced Edmonds, a New Zealand company which produces baking powder.
The Edmonds Cookery Book was first published in 1908.
I used a 13- by 4-inch (34cm x 10cm) rectangular tart pan but one could use another pan of similar dimensions. Such as an 8-inch (20cm) square cake pan or a 20 x 30 centimeter rectangular pan, which the original recipe called for. If using a cake pan, one neat trick is to line the bottom with a wide piece of foil leaving an overhang over the sides of the pan, then smoothing the sides and buttering the inside. Once the bars are finished, you should be able to lift the foil (and the bars) from the pan easily.
The dough may take a bit of coaxing to bring it together. If necessary, dampen your hands and knead the dough until it comes together. (It doesn’t need to be perfect.) Transfer the dough to the pan and use the heel of your hand to press it evenly into the bottom. Even if you think it looks goofy when patting it down, it will bake up nice and flaky.
Note: The only substitutions I could imagine that might work for this recipe might be honey, since it has the same viscosity to golden syrup. Rice syrup is another possibility. If you do try it with another liquid sweetener, please share your results in the comments.