The coordinates above are not for the cache location. They are for St. James Park, in the centre of Bristol. The cache is within 200m of this spot. There is nothing at this location that will help to work out the coordinates.
There is an audio file which is necessary to find the coordinates. The link can be found below, and takes you to my Dropbox account where I have hosted the audio file. You will need to download this. The audio file is 828KB in size, has been created by myself, and doesn't contain anything harmful.
Please contact me if you have any problems downloading the file or with the cache itself.
The cache is a magnetic nano, and the area is muggle rich, so please exercise caution whenever retrieving!
Alert: You are about to download a file that contains further details needed to find this geocache. As the cache owner, I represent that this file is safe to download although it has not been checked by Groundspeak or by the reviewer for possible malicious content. Download this file at your own risk. Dropbox Audio File
You can use this link to check the coordinates you have worked out to see if they are correct: Link To Geochecker
Enjoy :)