Thanks @JammyDodger
Is there a way to disable core plugins at startup so I can test if the Chat plugin is the issue?
The Bitnami chart allows me to pass a list of plugins and it will run the command RAILS_ENV=production bundle exec rake plugin:install repo={{ $plugin }} for each plugin I supply BUT I think that will be on top of the core plugins.
I will look at the standard installation again - we deploy all our 3rd party apps using Helm charts in our kubernetes cluster but maybe it makes sense to make an exception for Discourse if kubernetes and helm support are a long way off.