This is a tough one - a whole case???! It's no longer in production - so you would have to attend auctions, scour the net, etc. Try going to the McTears (http://www.mctears.co.uk
) to see if they have any - and start bidding! But then again, you're talking about a whole case, so that could be very difficult.
Here's a good article from the University of Glasgow about Red Hackle -