It would appear that this is another one that's just too well hidden for us! Then again, if this is a one-star for difficulty, were we even in the right place? We're fairly certain that we did the maths correctly, and the coordinates took us right down a tarmac road. Also, when we reached the location indicated by the GPSr, there was a massive trodden-down patch in the grass, leading us to believe that perhaps we weren't the first to have visited recently. (The last logged visit is by Zetetic, almost one month ago.) I guess we'll wait and see how others fare with this challenge.