I was able to watch this ok bawn ... I'm in the UK. I played it through again today for the friend I traveled to Ireland with. We had a conversation along the lines of how do you prove any stand alone rock art is prehistoric. My initial response was to say there should be other evidence/finds that can be carbon dated but I doubt if this was the case with a large percentage of rock art.
I have N.L. Thomas's book Irish Symbols of 3500BC (1988). According the author the spiral symbol represents the winter sun or the summer sun according to whether it is clockwise and closely wound or anti-clockwise and loosely wound. If this is still an accepted theory then perhaps the Corr Aille spiral represents the end of the harvest year and the onset of winter.