Here's a brief tutorial for removing watermarks.
1. Download and install https://www.pdfgear.com/pdf-editor-reader
2. Click "Open File" on the left and select the PDF / Drag and drop the PDF into PDFgear.
3. Click "Edit" on the top.
4. Click "Edit Object" on the top.
5. Press Ctrl+F and type in a portion of the watermark text.
6. Click on the < left or > right button to move between search results.
7. Right click on the watermark on each page and click "Delete" / Left click and press Delete.
8. Click the "Save As" icon on the top left.
Or... upload on google drive/mega and send it to me and I'll remove the watermarks using a Preflight script which takes 2 seconds.