Visited 17.7.10.
The road leading to Farmington goes straight through the Hillfort. As you approach from the west there is a house to your right and a stone on the left which is engraved Farmington MM. This is where the western 'defences' are. All that can be seen is a slightly raised mound leading off into the field. At the eastern end of the 'defences' can be seen a low raised bank where the field boundary hedge now is.
There is in truth very little to see and is hardly worth making a special visit for.
Visited 5.9.2009, walking up from Northleach along the Monarch's Way. The first sight of the "fort" comes over a gate, where the by-road takes a kink to the NE just south of Bunker's Hill. From here, the defensive line of the southern side of the site is visible - it appears to be defended purely by a scarp slope, with no obvious rampart or earthwork.
It's a very large site, and as none of the ramparts (E and W sides) or slopes (S and N sides) would appear to be particularly formidable, I can only guess that it was more of a settlement site than a true defensible hillfort. The internal area alone would make any kind of sustained defence almost impossible unless you had a very large garrison to man all of the palisades (assuming there were palisades).
At the western end, inside the rampart, can be seen the ghost of Farmington long barrow and the farm inside the fort produces ice cream. The western rampart is the most "impressive" but is still very low and has no natural slope to assist.
Leaving the fort to the east, the eastern rampart follows the line of a hedge and again if you didn't know to look for it you wouldn't even notice it in all probability.