I currently study Human Sciences at UCL. The advice that you can't get in without a science A-level, is wholly untrue. I have friends in this exact position studying the course right now. It is preferred just to make it easier as the first year is very biological science heavy. In your application, make sure to express why you are interested in what you will study.
For inspiration of what you'd study, look at the modules of Human Sciences online and perhaps the reading lists of what you'd cover. You can then pick an area that interests you and expand on it. For example, Gastrulation in the Anatomy and Development module, Psychology of mental disorders in the psych module, or the physiology of the respiratory system in the mammalian physiology module. From the next year, you will have so so much to choose from. I am not studying any biological modules as my interests from A-level have evolved.
This is just to prove that the lack of a Biology A-level or science a-level doesn't matter as much, and shouldn't stop you from applying and succeeding as long as you show genuine interest and passion.