@slambe @woodcock_mike
Take the back up of the DB first just in-case.
This has to be done from ranger DB, following querries may help to get rid of deleted server form the plugin status page:-
select id,service_name,app_type,host_name from x_plugin_info where host_name='HOST_NAME';
Where HOST_NAME is the host that has been removed form the cluster, verify the details.
To remove the plugin status info for the removed host run following query:-
DELETE FROM x_plugin_info where host_name='HOST_NAME';