Installing an Ansible Module

I apologize if this is the wrong area, I have spent a few days search for an answer on this without success. I also signed up for Gold hoping to get support, but it seems this is out of scope :frowning:

We currently use Teamcity / Octopus for our devops, building and deploying applications and infrastructure to AWS using Ansible playbooks with AWS Cloudformation. We have over 30 of these pipelines and they work fine and can be ran independently with Ansible if required.

Iā€™m reviewing as a hosted replacement to TC / Octopus and hoped to do a quick PofC lifting our ansible scripts.
I have using the image image: williamyeh/ansible:ubuntu18.04 and have installed a number of pre-requisites

We use the ansible module ec2_instances for dynamic invenrories among other things, and these seems to be installed when I search for the file on the runner, you will see this in my gitlab-ci.yml and output log below

My ansible playbook suggests the module is not installed and when I run ansible localhost -m ec2_instance I get an error