If I am getting the same document signed just personalised for each person can I create a field overlay template so I don't have to add all the signature fields each time (it is a policy manual so signatures and dates are required on each policy)
Do you mean that you want to always create the same field in the same location? If so, you can do it by creating a blank page with that field and then use the Replace Pages command on it to replace the blank page with the actual contents. Just make sure you save it under a new name, as to not overwrite your template document.
Another option is to do it using a script.