In the cache you will find a letter and a number which you should take note of and use it to help you find the Bonus cache.
From No 8 continue a short distance to the well made track/drive. Turn left shortly followed by a right, and then after a short distance in the trees turn left again. From here continue in a northeast direction across the fields.
Unfortunately, the entrance to this path has gone/grown over along with the entrance to field at No9, and the path across the fields to No9 and No10 have not been made up. I have reported this to OCC so hopefully it will be resolved! You can get through to the path, but it isn't the best of walks at the moment so apologies for this.