Upgrade from 9.3 to 9.4 issue

I have just upgraded from Fedora 21 to 22.
This included an upgrade of PostgreSQL from 9.3 to 9.4 which causes postmaster
to fail because the existing databases are still at 9.3.
As suggested, I then ran postgresql-setup --upgrade but this failed with:

Performing Consistency Checks
-----------------------------
Checking cluster versions ok
Checking database user is a superuser ok
Checking database connection settings ok
Checking for prepared transactions ok
Checking for reg* system OID user data types ok
Checking for contrib/isn with bigint-passing mismatch ok
Checking for invalid "line" user columns ok
Creating dump of global objects ok
Creating dump of database schemas
books
postgres
pots
stocks
template1
ok

lc_collate cluster values do not match: old "en_US.UTF-8", new "en_AU.UTF-8"
Failure, exiting

How can I recover from here?

Cheers and thanks,
Stephen Davies