We have a discovery rule which is successfully finding a server however it's not applying templates which leads me to believe it is not matching it against any Discovery Action.
We have numerous discovery actions which are checking "Received value like xxxxxxxxx" how do we manually see what information that host is sending as "Received value" to the proxy?
Assuming that you are talking about network discovery (sidenote - it is always a good idea to say which exact discovery you mean). In that case, "received value" depends on the discovery checks you have. For example, ICMP ping would have no received value. SNMP and Zabbix agent can be tested with snmpget and zabbix_get, and so on.