Depends on what topics you enjoy in biology.
Biological sciences would give you a general overview of all the topics related to biology in which you would get choice to specialise in your third year with the topics you enjoy. So if you're unsure about what topics you find interesting, biology may be a good choice.
Bio-medical science is more specialised on health and disease. You would cover topics like cell biology/physiology/Genetics/Hematology etc.You get less range of topics as the degree is more specialised, for example you wouldnt study topics such as evolution or plant biology as you would in a normal biology degree. I've heard biomed been described as a half way point between biology and medicine.
So it comes down to you. If you want a general overview of everything, go with biology. If you're more interested in human biology and disease I would go with biomed.