Hi,
1. Supposing that you're using the HikaShop Filter module to run the search with the filter system, I would recommend to turn on the "force redirect" setting of the module if that's not already the case, and then, in the "menu" setting of that module, you need to enter the id of a menu item configured to display all your products (a menu item of the type HikaShop products listing). And then it will work like on our demo website.
2. Could it be that the banner position is not available on other pages ?
If the module is configured to display on all the pages, then it will display on all the pages as long as the position is available on all the pages. Besides, that I don't see another reason.