From the delightful Ettrick Bay take the minor road north along the shore. Just before you reach the parking area (where the road narrows) you will see a metal field gate on your right. The chambered cairn is visible from this gate - 2 minute walk away.
It appears I an following in the footsteps of Mr G with these reports. I am sure there are worse people to follow!
I have to disagree with Greywether about this site. I think it is well worth visiting, even if you don't get chance to visit the other sites in the area (like me!).
The surviving cist, in situ, with capstone, makes the trip worthwhile in itself. Once you factor in the superb coastal views over to the mountains of Arran it becomes an obvious place to seek out.
After spending a glorious day on the beach in the warm sunshine (a rarity no doubt) it was a great way to end the day. My last site on Bute before heading back to the mainland. Bute is an easy island to visit and small enough that you could see all the main sites in a day if you so wished. We had two nights which seemed just about right. I also managed to knock another 3 Historic Scotland sites off the list for good measure! :)