Haha! No worries Tiompan chap.
Reason I had stuck a couple of threads up previously was to explore criteria like this and see what people thought before I went ahead and posted. So yes, tis NEAR a boundary...but not one - the boundary being a stream, and just west where the boundary does loop away from the stream it looks to very much preserve a fossilized former loop of the same...
Neither is it marked as a 'BS' on earlier OS sheets, which I guess presents its own set of problems. But its not recently set as a vanity stone I wouldn't think - it isn't in a home paddock with easy visibility from a house, yet it does seem to align quite nicely with a number of stone age features SW...and a hulking great chunk of rock is it too!
Chris