Civil War Earthwork

At the weekend Lincolnshire Tom forwarded some pictures from one of his FaceBook groups asking if I'd ever heard of a particular earthwork near Laceby in Lincs. The answer was that this was a complete surprise. Especially as I'd passed close by several times on the A18 on my bike as a teenager, and across the fields when out walking a few years before that. My big question is why there; why is there an isolated fort in that specific location. Puzzling. Answers on a postcard (or blog comment) please.

Would the roughly rectangular features inside be signs of an old building? A Manor House perhaps. The whole fort measures c200 x 100 yards.

For a little more context here is a map of the wider area. The built-up place to the top right is the western edge of Grimsby, which would have been a small town of 1-2000 people at the time. The only other relic of the Civil War that I know of (though I don't know for certain that it is) is a ditch and bank around an old farm building in Old Clee, Grimsby, off map to the top right.

The earthwork is circled in the bottom left. It looks too far from the junction of the roads, and from memory it hasn't a clear line of site owing to the lie of the land.

Barton Street (the A18 in this stretch) roughly follows the edge of the dip side of the escarpment formed by the Lincolnshire Wolds. Along this line are several springs which are the sources of several streams, or becks, one of which becomes the River Freshney which flowed into what was then the harbour at Grimsby.

If I'd known about this 5 1/2 years ago I'd have woven it into my narrative Lincolnshire campaign.