Hi @Chris Jones ,
There is unfortunately no way to force pulling a new image with the same name and tag.
You can delete and recreate the container group to force pulling the new image, as described here. For clarity I'm quoting the document below:
When you delete a container group and recreate it, it's not "redeployed," but created new. All image layers are pulled fresh from the registry, not from those cached by a previous deployment. The IP address of the container might also change due to being deployed to a different underlying host.
I found other suggestions online, but cannot confirm if they work or not, feel free to test them :).
This is by design to always have the images cached for faster operations and restart times.
Please "Accept as Answer" if it helped, so that it can help others in the community looking for help on similar topics.