I am looking to have a Cloud SQL MySQL instance have a read-replica in another region - within Cloud Sql.
I'm aware I can create an 'external replica' but I'm unaware / unable to create an 'external replica that is Cloud Sql'.
It would be very ugly to have a master sitting on the "Managed Service Cloud SQL", and be forced into a VM Mysql, in other regions.
Any help would be hugely appreciated.
Cloud SQL does not currently support read replicas in a different region that the master instance. As you mention, a self-managed replica can be used.