wp_actionscheduler_logs has increased from 5 to 118 MB overnight. It generates 50 or 100 entries per second with message ‘action ignored via WP Cron’. The log_id in each case is 0.
I should have said that I did a ‘quick’ export from phpAdmin in my old server. I still have access to the databases there, so could do a custom export if that would help.