Clive,
Yes, you are correct. You would require a mix of XML and SQL.
That's one of the reasons we developed Datical DB. It uses the Liquibase engine but includes custom extensions for Oracle to support database objects that are not in Liquibase. We also have the ability to Forecast changes without persisting them to the database, a Rules Engine to enforce standards like naming conventions or technical standards, and Deployment Packager to onboard SQL files into the XML format.
DM me and we can arrange a look at Datical DB.
Thanks!
Robert