Hi! I am looking for some override for category blog in London template.

I have a menu item with a category blog. I need to expand this to also include subcategories.

Page needs to be like this:
Category 1 heading
Category 1 description
article article article
article article article

Subcategory 1 heading
Subcategory 1 description
article article article
article article article

Subcategory 2 heading
Subcategory 2 description
article article article
article article article

Is this possible in some way?
When I try to add the subcategories, only the subcategory heading shows but no articles.