Anew

"These include a number of healed Head injuries apparently inflicted with blunt, club-like implements ..."

One might consider the possibility there was a stick-fighting tradition in Europe at the time, similar to that which exists in traditional/tribal Africa . This may explain some of the injuries of this type . At the same time, though, this tradition as it exists today is intended to provide contest below the level of war, so blows which seem intended to kill would probably have been due to battle .

"There are accounts dating back to the 1850's where people used to wash their cattle once a year in the bog..." (from the previous post)

The legend of Achilles may fall into this context . Dipped as a baby in the mythical river Styx, he was said to be invulnerable to attack in all places exept for his heel, (where his mother had held him).

Other flattened circles i have found plans for are as follows, (from Prof. Thom's book Megalithic Sites in Britain) :

Rough Tor
Dinnever Hill
Burnmoor E
Cambret Moor
Black Marsh
Bar Brook
Thieves, (henge)
Aviemore
Tursachan Callanish, (a complicated site)

With the (slightly) possible exception of the last, none of these appear to have rectangular settings of stones either within them or immediately nearby . Thus if that of Castlerigg represented an inverted entry ramp, and if the other rings continued to represent ceremonial huts, this aspect must have been dropped or shifted to a less fixed medium early on . This complicates, but does not rule out, its reappearance as the extra stone in the Barra grave .

It is also noteworthy that the North Uist site Leacach an Tigh Chloiche contains more in the way of rectangular boxes of stones, (4 or 5 by my count), than clear evidence of a ring . This raises the possibility that the rectangular stone setting was either a Hebridean innovation, or one which took root there . The former seems somewhat unlikely, but cannot be ruled out if the time held a sufficiently competent seafaring culture, and if so, their meaning is the more obscure . In any case, the way it is used at the Uist site indicates it could at the least be separated from any interpretation as an inverted entry ramp to a ring as symbolic hut .

Another aspect that i assume the common buzzard shares with hawks, eagles and the like is the habit of circling while on patrol . I feel this would have elevated these birds in the opinion of the ring-oriented culture of the Isles . And that such may be attested to by the Wandsworth Shield, which draws the ends of the bird-of-prey-and/or-carrion's wings into circles, possibly indicative of a regard for their (circling) modus ; (i note that this would be an Iron Age find, and thus substantially later, but think the Neotlithic/Bronze-Age belief system still had an influence upon traditions at the time) .

Also, as mentioned in other threads, i believe that when the sunlight shone down on gliding birds of this type, the image of a bucranium would appear as the aft part of the wings became translucent while the fore-part and body remained opaque . Though this would be most elegant with the lightly-muscled vulture, the more powerful (for its size) buzzard should offer a similar, though more stoutly horned, image . I feel that this too would have made an impression on the people of the time .

Thirdly, as can be seen in this photo, the underside of the buzzard's tail can display lines of dots which i feel might be connected to the fan-shaped array, "Hill o'Many Stanes", in Scotland .

Other birds, (besides vultures, ravens and/or carrion crows), have been suggested, and i think the choice of preffered agent was likely to have been regional one and at times a way of expressing tribal identity . Where spiral carvings and the common buzzard were both present, i feel it was their most likely choice . But an interesting counterpoint is provided by the backstory of Mên Scryfa in Cornwall . At least at the time the stone was erected, the locals held the raven in high regard . Ravens & crows being much different than the Buzzard, (among other things, they fly in iconically straight lines, and are more flock-oriented), their veneration may indicate either changing times or a distinctly different local culture, (if excarnation was practiced in Iron-Age Cornwall, or if the tradition reached back into the Bronze Age / Neolithic) .

Now that i am aware of a hut quite close to the Urkultur which's floor-plan resembles the rings mentioned above and the grave, its connection to the immediately-just risen sun seems less probable than to a symbolic dwelling, (perhaps) for some rite of passage into the afterlife . With this, comes a de-emphasis, (though not necessarily dismissal), of the possible role of excarnation here, and i think a separate thread on the subject would be better.