I have not had time to read through all of this so i'm sorry if this is old news.
As i work for the university i have full access to
http://www.scran.ac.uk
This is the digital image archive for the Scotsman and others. There are 1039 images/digital media/maps/drawings related to Portobello on this site. 1000s more for east coast.
Let me know what you're looking for and i'll download it if it exists.
cheers