Found what the issue was,
It looks like you can publish remote apps and desktops under the same host group but if you assign them both to a user only the desktop shows up.
When I created the Host Group the desktop is automatically published then when I created a Application group to publish e.g. Access and I couldn't list it on the web gateway or the Remote Desktop Client.
Once I removed the Desktop assignment from my test user I could see and launch the Apps.