I asked an old seaman, from roughly the area of the disaster, about the "from Yarmouth DOWN to Scarborough" line. He told me that "up and down" as the map shows towns is irrelevant to the old-timers. Indeed people here in the bush of Australia still use "up or down" seemingly at random. As in "I'm going down to Melbourne" or I'm going up to Melbourne" (Melbourne is pretty much directly East of here - neither up nor down.)
Cheers, Joy