I visited the site of the now disappeared Longbarrow about 5 years ago. It is referenced on the Salisbury OS map.
I rarely see any internet posts regarding it’s proximity to Figsbury Rings, though I am as blind as a post. It’s approx 1/3 mile from Figsbury and in site of.
This suggests to me that Figsbury has a Neolithic precedent, as the Longbarrow is dated 4000 BCE.
Also, of interest, is that Clearbury Ring is visible from the barrow site.
Well I never, I certainly didn't realise it was there when I went to the strange Figsbury Rings (it's only on the orange os map it would seem). So what is there left of the barrow, I'm assuming there's a vague lump in a field? Or is it just flat?
I would say a vague bump, but that could have been wishful thinking.