Dear @andy-thomas-83,
The fact that it is difficult to override the docker image registry for just one service is a problem. I will fix this in the next release. The various DOCKER_IMAGE_* configuration values will be set to, e.g:
DOCKER_IMAGE_OPENEDX: "{{ DOCKER_REGISTRY }}overhangio/openedx:{{ TUTOR_VERSION }}"
This way, you’ll be able to override DOCKER_IMAGE_OPENEDX without touching DOCKER_REGISTRY or having to define your own private deployment file.
Does that sound reasonable to you?
EDIT: see this commit https://github.com/overhangio/tutor/commit/bbd92223eee4a17b6b59e81dfea084388b28dc98