Anybody got any idea about this site?

In Monk Wood just outside Alton in Hampshire there are clear signs of earthworks which have become quite heavily overgrown. The Ordnance Survey map simply says "Earthworks" in its usual old english style. I've walked past them a few times and wondered. They seem to be very steep sided which points towards something more recent than the usual range of sites covered by MA, but I couldn't help wondering if any other contributors have seen them and perhaps have some info. They're beside the Hangar Way footpath.