We are using a card variable in a child shape, which is then also being used on the parent visual overview, obviously for each control panel using the child shape visual overview and when typed in it fills it in for every panel that is using the same visual overview panel child shape.
Is there a way to stop this from happening as each panel will have different information used in in.
A card variable indeed shares a value for any Visual Overviews that are shown inside a card. This includes embedded Visual Overview or separate pages.
If you want separate values when embedding pages, you could opt to use page variables. These variables can have a value for every Visual Overview page. More info on the different scopes of variables can be found on the docs.