Visited 31.5.12
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!