Unfortunately missed these... I would say due to the somewhat misleading RCAHMS nomenclature... but that would be unfair since I was in no fit state to visit anyway back in May, following a day upon the sacred summit towering above.
To reiterate the discussion findings, note that this site has nothing to do with the great cairn crowning Beinn Na Caillich, but – according to 1:25K OS map (they are not depicted upon the 1:50k) – consists of two chambered cairns within forestry at the co-ordinates given, that is in the vicinity of the Broadford River.
I’d suggest taking the Old Corry road just outside of Broadford and, parking near the Electricity Sub Station, it would appear an audience can be gained by following the pylons beyond (to the approx south-east), keeping a little to their right. Perhaps. Might need to cross a water course, so happy hunting!