Forewarned is forearmed eh?
Top tip for future signs like this - maybe give two hints on the sign:
 Which ambush
 Which war
I was sure we were heading towards Béal na mBláth. We got there and it was Kilmichael.
Obviously put up by the same guys who did the signage in Killarney. Every single junction there has signs for City Centre for all of the directions in and out. We also discovered that via Kilmichael is not a shortcut from Bandon to Killarney.