MartinR, you are a genius! The artwork was indeed in the churchyard of the church of St Mary the Virgin in Upchurch. It is or was (I don't know because I haven't visited since I took the picture) behind the church so GSV wouldn't have been any help anyway.
And there was I thinking I was being cryptic with my clues so far. Further clues would have been that the village stands on an ancient road, so ancient in fact that it pre-dates British history. Also that there was a Roman settlement on the site and that a famous pottery was located in the village.
Over to you.....