OK - I have it working. There was indeed a problem with the ActiveMQ servers master / slave configs in the broker.xml files for each. The sections <ha-policy>, <cluster-connections> were entirely missing, and the <connectors> only had the local host defined, and not the other one.
Thank you Justin for pointing me in the right direction! -- Sent from: http://activemq.2283324.n4.nabble.com/ActiveMQ-User-f2341805.html
