Lovely hill, extremely windy when I went up in December. I ascended up a path from the quarry side and beside a gate saw a bunch of stones which seemed to me could well be a former stone circle, although I cannot find anything on the old maps to confirm that. The stones are piled up at 57.664767, -2.715907.
As an aside I was using peakfinder.com to identify the hills I could see, what a great tool!
Well, I went back and the stones lying at the side of the field had all been removed. The area is being cleared for agriculture. There are still two HUGE stones sunken into the ground, I hadn't noticed them before :) What reminded me about them was I visited a local farm today and asked the old farmer if he knew anything about them but he said didn't. It's a real mystery.
The two stones are at NJ 57316 64164 and NJ 57333 64200, visible on satellite maps. I'll add pix now.
The 1887 Banffshire Advertiser article does suggest there were two stone circles on Durn Hill but I haven't found any other indication.