Just installed, it's re-indexed everything fine and is working great now.
Many thanks for the fast turn around.
Unsurprisingly it was asking to rebuild the index, so I clicked the rebuilt button, but it never completed.
Doing a bit of detective work, it seems to be, where it drops all the tables, then recreates them I'm getting the following:
[12-Aug-2020 13:38:08 UTC] WordPress database error Specified key was too long; max key length is 767 bytes for query CREATE TABLE
id int(10) unsigned NOT NULL auto_increment,
tid bigint(10) unsigned NOT NULL,
tsrc varchar(255) NOT NULL,
tdt datetime NOT NULL default '1970-01-01 00:00:00',
build_time int(11) NOT NULL default '0',
update_dt datetime NOT NULL default '1970-01-01 00:00:00',
force_rebuild tinyint(4) NOT NULL default '0',
locked_dt datetime NOT NULL default '1970-01-01 00:00:00',
PRIMARY KEY (
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci made by do_action('wp_ajax_wpftsi_submit_rebuild'), WP_Hook->do_action, WP_Hook->apply_filters, WPFTS_Core->ajax_submit_rebuild, WPFTS_Index->create_db_tables
Talks about making sure indexes are the less that 191 long. Is there a way out of this, other than going back to the old version?!