Thanks for the feedback guys. I got this answer from BL support
Although we have change the layout of our web store in recent times, and we are still making changes, within in each main category there are sub categories that will see once you have clicked on the main category button.
We are planning to create new categories for many of our long running, and soon to be long running series such as the Primarchs books but you can use the search bar to look for items as well such as the Space Marine Battles books.
I won't tell them again that categories and search function are useless but hopefully there is bright future and BL layout will be soon changed according to answer.
I remember, how I once contacted BL support and was complaining about quality of book spines and how wrinkles appear immediately when book is opened for the first time and that books from other publishers don't do it.
And they told me to not open books so wide... So again it is enough for me to not contact support for next few years.