OK, finally beat it and got it working.
Where it asks for: "Facebook user id, page id or slug"
Put in the number you see in facebook when you navigate to the page you are trying to feed on.
For example, in my case, it was:
That number at the end was what I needed (even though the plug in claimed to be working with other names / ID's for the facebook page). Maybe this is quirky because it is a community page, who knows.
Also, you had to do the rest right (create the cache directory and set up the app ID).