There is also a Church Micro in Warnham (#20 so one of the originals!), a Cricket Pitch Micro (#23) near the given parking coordinates, and a few caches named after cartoon characters which you can collect in between these ones. Note: some paths can get very muddy at times so appropriate footwear recommended.
There is plenty of parking on street in Warnham or at the Village Hall (see Additional Waypoint at #1).
Another nice view of the Deer Park from here.
Highlighting due to comments that the way after this is unclear ... After this find continue to the road, turn right at the second driveway, and take the footpath through the Deer Park. The footpath sign pointing through the deer park is on the other side of the road.