This kind o f information should be on a master page in ID that you assign to all of the documents where required. To be able to edit-once/update-many you should make the footer information a separte document, then place that document as a link in the master pages.
Thanks for the info. I av just about an idea how it might work but is there any tutorial I can follow?
Also all inDesign files get updated at once but then I have to go to each and create pdf anyway right?
I don't know of any tutorial offhand that specifically addresses using a "master document" that you would place into a new file. It's just like placing a graphic, though.
Start by creating a .indd file (or an Illustrator file if that seems more appropriate) that will fit into your footer area and create the entire common footer content in this file, then save. Place this file, whether .ai or .indd or any other format on the document master page of the file that will become your 40 PDFs. Next time there is a change edit the placed file and update the link in the larger file.
You do need to make new PDFs every time. If all of the versions are in a single .indd file (or combined as single files in a Book (.indb) then there is no major work involved in exporting again. Pages can be extracted to sepatate files from Acrobat Pro, or you can look for a script (ask over in InDesign Scripting) that will export as single pages directly from ID.
This issue of synchronizing multiple INDD documents is easily handled using the InDesign Book feature.
The image above shows how you can make edits to a single associated file (master page elements as well) and then every other associated file will be forced to inherit the same changes. Magic? No, it's just clever coding.
1. Create a new "Book" file
2. Add the files you want to be part of the book (they don't need to be part of the same book, but they should share common elements)
3. Assign one of the added INDD files to be a "Style Source"
4. Options will ensure you retain consistency across all included documents.
5. You can even produce PDFs from the "Book" toolbox without having to open each one individually
I trust this will streamline your process.