I`m using the above plugin
Bitbucket Server (not cloud) 5.5.3
SVN Mirror for Bitbucket Server plugin version 3.3.15
There is a admin dashboard that shows all enabled, and active synchronisations.
When I click on disable, they disspear from the list, and the only way to find them again is to go to the relevant repository, and re-enter the config, and re-enable the synchronisation.
It seems that the Instance wide, and the project wide pages that show all running SVN synchronisations should have a filter to show me:
All Active synchros
All Disabled synchros
ALL synchros