Visited 14.03.2016
If travelling North on the A39 from St Columb Major, once you reach the Roundabout at Winnard's Perch travel for almost exactly 1 mile and there is a lay-by on the opposite site of the road, pull in here and walk back on yourself for until you see a silver gate on your left and behold... The Nine Maidens!
They are on the far side of the field and as others have said, the bogginess is far worse than it looks, so wear Wellies.
I also discovered that there was a composer named George Lloyd who's first opera contained a piece 'Iernin', which was inspired by The Nine Maidens standing stones near St Columb Major, and tells the story of one of the Maidens who comes back to life as a fairy.
Source:
en.wikipedia.org/wiki/George_Lloyd_(composer)
Now on to the 2nd part of the adventure which will be tracking down this musical work to listen to while I admire your photos and my own!