Problems along the way

Firstly, the various problems I came up against.

• Whatever I tried, I kept on getting Server 500 errors whatever I tried at the WordPress installation.
• Most suggestions are to try 'localhost' or 127.0.0.1 as the hostname of your database (assuming it is on the Synology box).
• The only thing that worked for me using MarioDB 10,  was 'localhost:/run/mysqld/mysqld10.sock'
• Many thanks to Yves Lacroix whose comments on Sridhar's musings got me past that barrier.
• Wordpress itself needs direct FTP access to each of your sites, if you ever want to install new Themes, or plugins, or . . .
• That means that each site needs a separate user, and each of those users needs direct FTP access to the wordpress folder for that site.
• Synology does not make it easy (or even possible) to create a shared SUB-folder, nor to point web site root to a user home folder (which would have been easier).
• That resulted in my deciding to create a new shared folder (at the top level) to hold the wordpress software for each of my sites.
• You will of course need to access your Internet Router and setup 'Port Forwarding' both 80/443 for web traffic, and 21 for FTP, to your Synology box.  I have a BT Home Hub on which it is very straightforward, but see my detailed post shortly!