Tweak to national route merge task - start at lowest national route of type, not route of type overall.
Tweak to national route merge task - start at lowest national route of type, not route of type overall.

mysociety/fixmytransport,mysociety/fixmytransport,mysociety/fixmytransport,mysociety/fixmytransport,mysociety/fixmytransport,mysociety/fixmytransport