Content module > missing modules

I have the following modules set to display om the Shop page only, using menu module assignment (display on selected pages only):

Shop menu
Shopping Cart

I added the Content Module (displaying on brand) but if you click on a brand, the above modules vanish. I assume this is to do with somehow needing to assign the modules to display on the page displaying products by brand, but don't see how to do this.

Strangely, I also assign User Login menu but to 'display on all pages' and this does not vanish!

I attach an image which may help you to explain to me if you can. Thanks in advance.

It's already set to (Hikashop hidden menus) 'Menu Item for category listing module 110'. Is this what you mean? Thanks.

I had to assign the modules I wanted to display to the menu 'Hikashop Hidden Menus' > Menu Item for category listing module 110