Inschfield Farm seemed to be the correct place to ask permission on this visit. Two routes were offered: our chosen one through the farm then up to the right (which had just been harvested) or park at a layby a little NW of the farm entrance then up through two fields.
I popped into the Inschfield farm to ask for permission, and found an old guy scrubbing the floor of a barn. He had an accent that went beyond comprehension - more to do with age and rural isolation than Scottishness I believe - and even though I couldn't understand him, he seemed unfriendly but obliging, so I just went up. As it turns out, the circle looked like it may actually be in a field connected to the next farm, Nether Boddam (!), but it was fallow and no one was around, so hey.
A wonderful view from this place - the smashed and fallen recumbent obviously used to line up with the foot of Dunnideer, and Tap O'Noth clearly looms off to the west.