As Kammer correctly predicted I did indeed arrive at the cairns before the stone circle.
The larger cairn is about 1 metre high x 10 metres across.
The smaller cairn is about 0.5 metre high x 8 metres across.
There were plenty of sheep and lambs milling around the cairns and most ran away as I approached. One mother sheep had different ideas and headed straight towards me. I stood and watched as she got closer and closer. At one point I thought she was going to ram me (excuse the pun). But she stopped a few feet away and stared at me intently until I left!
Visited 1st August 2004: These cairns weren't high on my list of places to visit, but William and I came across them on our way to Airigh Na Beinn Bige stone circle. Because of the topography of the hillside, there's a good chance you'll get to the cairns before the circle.
They're both pretty large, and the northerly one is obviously a cairn (you can't miss it). Both are slightly to the east of the circle on the same plateau. For directions to this site see my fieldnotes for Airigh Na Beinn Bige circle.