Ooops! Just updating these notes as last time I visited and posted I was looking at an 18th Century chalk pit, not a Neolithic Causewayed Enclosure!
The remains of the enclosure are actually up on top of the hill, just to the North of 3 bowl barrows (and, more prominently, a covered reservoir). The chalkpit has completely eaten the whole side of the hill, and taken the eastern half of the enclosure with it. Only a visit can make you appreciate just how much damage was done to the hill by chalk quarrying. One side of the site is a sheer quarry cliff.
What is left is a large C shape of 'causewayed' banks and ditches, the top half of which disappears into the woods on the northern slope.
However, this is all barely perceptible now, especially as the site appears to be returning to woodland quite rapidly. I scurried around like an idiot looking for something bank or ditch - like to photograph, but to no avail! You can just perceive some of the earthworks in the scrub, but it is nigh on impossible to trace any distinct circular pattern. Maybe better in the winter. Times like these you wish you could fly and get a bird's eye view. (Although the multimap aerial photo doesn't reveal much either)
Frustrated at the lack of obvious monument, I turn my attention to the setting: this is such a beautiful spot, and it's location at the very edge of the Downs may have made it a special, boundary zone for early settlers. I know I will return again later in the season, and sit and feast on some of these wild strawberries that carpet much of this site.
Access: Park in Offham Village near the Church, cross the busy A275, over a stile and take the steep footpath up the side of the hill until you come out at the chalk pits. Look up to the escarpment on your right and you will appreciate how much of the hill has been taken out. Carry straight on into the woods on the other (south) side of the chalk pit and climb the path that curves round to the top of the hill. You pass another dizzyingly deep chalk pit on your left. Don't get too close to the edge! Bear round to the right and you will see the fenced in reservoir atop the hill. The 3 bronze age bowl barrows are at the NE corner of the reservoir, and the enclosure is just to the NE of the barrows.