Ok, having toyed around with this some more, if I leave the original code (from Unprotecting VBA Project Password (Using a password that you know)) exactly as it is, it works. However, as this file will not always be stored in the same place with the same name (the file is a form used to submit information relating to setting something up on our systems), I want to work with the Active Workbook. This seems to be where things start falling apart, though I cannot understand why.

To summarise:
* Creating a new Excel instance and opening a file from a specific local location, works.
* Creating a new Excel instance and attempting to work with the current file, doesn't work.
* Using the current Excel instance and opening a file from a specific local location, doesn't work.
* Using the current Excel instance and attempting to work with the current file, doesn't work.

Does anyone have any ideas, because I am drawing a complete blank.