The first round cairn encountered on the way up from the stone row. The large slab in the foreground may be a dismounted capstone. This would make it number 5 on Gladman’s Miscellaneous list. Looking towards Allt yr Esgair, Buckland Hill and Mynydd Llangorse.
Image credit: A. Brookes (1.5.2010)
The capstone assumption's certainly plausible in my opinion, but particularly liked the ring cairn. A true 'lost site', if ever there was one.
Actually, sorting the photos has made me a little more certain of the numbering, compared against the map on Coflein and the descriptions you posted. What it also highlights is that the OS have shown most of the northern cairns (i.e. apart from your numbers 1 and 6) in the wrong places on the 1:250000.