Doesn't really come as a surprise that the bluestones were used prior to Stown'enge ("where the Vikings dwell").
If you've been lucky enough to scale the Preselli hills from West to East (and back), the landscape and immediate environs are of so wild and breath-taking a nature that it would be remarkable if our Neolithic forbears hadn't constructed something epic to celebrate the place and their place in it. I find it hard to believe that the only evidence of their 'being there' was the piffly, off the summit Bedd Arthur in terms of stone circles near the quarries.
Further to the North East, at the Western end of the Preselli Hills (about 5 Km) is the super imposing Mynydd Carningli which literally towers above the landscape like some enormous volcanic elemental overseer, then you've the two smaller, less imposing hills of Mynydd Castlebythe and Mynydd Cilciffeth closer to Preselli, it's deffo a place to dream and contemplate our place in the grande scheme of things, that's fer sure.
There are quite a few natural bluestone out-crops all along the hill top, from about the middle onwards, but mostly to the Eastern end near the equally imposing hill of Foeldrygarn.
It'll be exciting if they manage to track down the site of the bluestone monument, would deffo hoof it up there for another butchers, that's fer sure!