Sincere apologies to all who have been waiting for assistance. For some reason, my notifications weren't coming through for the past few posts.
To clarify - I amended the files you list and I ALSO added the other files to the site - is the latter correct or do I just amend the files listed on your notes?
@SASSYSARAH and SPHINX767 - The general installation process involves copying (and overwriting) the files in each of the directories (as opposed to just copying over and replacing the directories and their contents). If any of your codebase has been customised, then you will need to go through the files, and manually add in the PayPal-specific changes. I appreciate that this is a painstaking process, and far from ideal, but we are still working with our developers to figure out the best way forward.
There doesn't seem to be a way to do this via the configuration, but you can force this behaviour by adding a line of code in the file:
Go down to approximately line 372 of this file (I am going by the 180 release), and add the following code:
$params['ADDRESSOVERRIDE'] = '1';
Are you referring to the big yellow "Checkout with PayPal" button? If so, the buyer will be returned BACK to your store after they have clicked "Continue" from the PayPal page. At this point, it should show a confirmation screen, where the buyer can change addresses etc.