so I ran: ANSIBLE_TAGS=composer vagrant provision from my trellis local directory.
but I have still have the same errors:
( ! ) Fatal error: Uncaught Error: Class 'Dotenv\Dotenv' not found in /srv/www/domain.co.uk/current/config/application.php on line *17*
( ! ) Error: Class 'Dotenv\Dotenv' not found in /srv/www/domain.co.uk/current/config/application.php on line *17*