Hi Peter

< so perhaps you are looking for a one-time wooded knoll rising from the valley. >

That's roughly along the lines I was thinking about. Checking the map of the region it's very low-lying with numerous flood plains - so it's gonna be a site raised above the general area and likely to stand out a bit (he says utterly speculatively!). I think it'll be a while before I turn my attention that way, so hope some other dood nearby might take a look around.