Ages ago when i looked into Dartmoors as a breed, showing wise. I was told that minimal white was best. Something like a star would be ok or small socks on one or two legs but not big socks or blazes etc. Basically the less white the better.
But then at most shows i've been to, especially local shows they're never too sure how to judge darties anyway (they seem more used to sec A's!) eg. (not my pony but a really nice Dartie once got the comment 'Not typey enough for a Sec A' - thats because it isn't one!!!) lol That was a county level judge judging a local show.
Shilstone Rocks do some really nice Darties that are always in the ribbons round here in showing/lead rein and general all rounder classes.