Robin Hood (2010) - 2 questions

Question: When the caravan that is moving the grain is captured by Robin Hood, he ties the men together and they are forced to walk back to the town ("17 miles" or so). Shouldn't they have used the metric system to state the distance they have to travel to the town? I thought stating the distance to be traveled in miles was just for the sake of the joke for American viewers.

Answer: A "mile" is not American in origin. The British adapted it from the ancient Roman term, "mille passuum," meaning one thousand paces or strides. Each pace was the length of five Roman feet, resulting in a mile that was approximately 5,000 feet long. This measurement fluctuated up until the Tudor era, when Parliament established the current measuring standard, though the metric system, which was developed by the French in the late 1700s, has since replaced it in Europe and elsewhere. Britain still uses mile as a standard measure of distance on road signs and for speed limits, etc.

Question: An interesting wind-up lute-type musical instrument is played at one point. Would such an instrument have existed at that time?

Answer: By "Wind-up lute", I assume you mean the hurdy-gurdy. Certainly, instruments fitting the description of the hurdy-gurdy were around in the time when Robin Hood was set.