Visited 25th August 2003: The Kew or Giant's Grave is a an unusual site. Just as I was getting the hang of interpreting the Manx burial cairns I found myself flummoxed by this strange selection of stones.
The Kew is a double row of stones, the gap between the rows getting smaller at each end. The stones all lean inwards in such a regular fashion that it seems unlikely that they've subsided. On the western end of the site is an old field boundary, marked with a hedge-bank. This is close enough to the stones to give the impression that some of the site may be buried underneath it. At least one large stone in the hedge-bank looked like it might have once been part of the monument.
The site can be viewed from the track that runs past it, but the hedgerow makes this a bit tricky. There's no public right of access to this site itself (something I didn't realise at the time of our visit).
There is, just outside Peel Castle a mound about 90 feet long known traditionally as the Giant's Grave [..] It may be of interest to note that the traditional giant of this grave is said to be the original of the three-legged Manxman, a legend which is suggestive of the many bodies found in these chambered tumuli, of which the legs are often found entire.
I do think Miss Buckland gets a bit carried away at times (but her urge to rationalise folklore is not unusual is it). From p350 in
The Monument Known as "King Orry's Grave", Compared with Tumuli in Gloucestershire
A. W. Buckland
The Journal of the Anthropological Institute of Great Britain and Ireland, Vol. 18. (1889), pp. 346-353.