One was near the path and well hidden in the heather to the south of the chambered cairn.
The other cist I saw is very easy to spot. It is right next to the path as you approach the cairn, just before the 2nd small wooden walkway.
And very nice it is too!
Three of the side stones remain in place and the cist is about 0.5m deep.
Well worth keeping an eye out for when visiting the cairn.