After much late night messing I've got this working and I like the results.
Using a Acer Aspire R3700 with wifi adaptor and LE10 as the server and a Amazon Firestick 3rd Generation using only wifi.
1. Install the addon and changed default password both to 'kodi'
2. SSH into the server and use a text editor to edit
/storage/.kodi/userdata/addon_data/service.mariadb/my.cnf
I removed the hash from below on both lines of # skip-grant-tables
user = root
pid-file = /run/mysqld/mysqld.pid
socket = /run/mysqld/mysqld.sock
skip-grant-tables
[client]
port = 3306
socket = /var/run/mysqld/mysqld.sock
skip-grant-table
3. Installed kodi 19.5 on the firestick
added the below advancedsettings.xml file to BOTH instances of kodi i.e. server and client in the userdata folder.
<advancedsettings>
<videodatabase>
<type>mysql</type>
<host>172.20.6.2</host>
<port>3306</port>
<user>root</user>
<pass>kodi</pass>
</videodatabase>
<musicdatabase>
<type>mysql</type>
<host>172.20.6.2</host>
<port>3306</port>
<user>root</user>
<pass>kodi</pass>
</musicdatabase>
<videolibrary>
<importwatchedstate>true</importwatchedstate>
<importresumepoint>true</importresumepoint>
</videolibrary>
</advancedsettings>
4. setup smb on kodi to share files using zeroconf.
5. setup video libraries on both client for movies and tvshows and setup and selected the default scraper.
and scanned for content.
I used user 'root' I probably I could have used user 'kodi' but it's a home media server not an international bank so security is of no issue.