MySQL 5 didn't start up from the preference pane so installed MySQL 8.

MySQL 8 didn't appear as a preference pane so had to remove the MySQL 5 preference pane and it did appear.

Exporting or importing data tended to get the error message The MySQL server is running with the --secure-file-priv option so it cannot execute this statement. MySQL 8 is more secure but for my usage needed to disable the extra security. Created a /etc/mysql/my.cnf file containing:

[mysqld]
local-infile=1
secure-file-priv = ""

[mysql]
local-infile=1

[mysqldump]
lock-tables=1

Inside the Preference pane for MySQL set this file to be read on MySQL startup.

Exporting data from MySQL using select ... into outfile resulted in files owned by _mysql which I didn't have access to. No real work around here apart from using sudo.

Trying to load a database dump from MySQL 8 into a MySQL 5 database got the error Unknown collation: 'utf8mb4_0900_ai_ci' . Had to set the character set to utf8 for the database by:

ALTER DATABASE <database_name> CHARACTER SET utf8 COLLATE utf8_general_ci;