I followed the instructions in https://idroot.us/install-php-7-3-ubuntu-18-04/ to install PHP 7.3 and then, as instructed, ran
a2enmod proxy_fcgi setenvif a2enconf php7.3-fpm
to enable it in Apache2.
systemctl status php7.3-fpm
confirms that php7.3 is installed and running and I did restart Apache2 using
systemctl restart apache2
php -v reports PHP 7.3.6-1+ubuntu18.04.1+deb.sury.org+1 (cli) (built: May 31 2019 11:06:48) ( NTS )
phpinfo(); reports PHP 7.2: PHP Version 7.2.17-0ubuntu0.18.04.1
What have I missed? Any guidance would be appreciated as I'm totally new to Ubuntu.