My network consists of an RPi3 hosting Piaware and a Ubuntu laptop hosting my webserver and a MySQL database.
I attempted to install the radar.php and mailer.php on the laptop, which went fine until I started to configure and test the email alerts.
After a failed attempt on the Ubuntu laptop I moved to the RPi3 but got similar result and no alerts via GMail. A search advised to install ssmtp as well as sendmail and once this was done and configures for GMail the email alerts started to work.
Having done the same config on the Ubuntu machine, that to also works.
Thanks for the scripts and your time and patience.