I have a list of 16 B&M's that I use to call every month when I was stock piling Penzance. You have to work for most things in life and this is no different.
When the first big scare came 2 years ago, and they were selling bags on Ebay for 80.00, I started compiling my list....and calling all of them, every week. Every time someone mentioned on a forum that they found a bag somehwhere, I would gather the info and add them to the list. If you sit and wait for an email notice, you won't get much in return.