By sheer coincidence, I drove through Curdridge on my way to Old Winchester Hill last Sunday!
Unfortunately I didn't remember any of the details from the post so didn't know where to look for "The Triangle"...
I did drive past the church though, and after re-reading the history I'm intrigued to find out more! I might have a nose around in the next couple of weeks...
Not sure it's prehistoric though, but will investigate further.