Iam already aware that freedom of speech and academic freedom are two separate issues.
Before we enter the circular debate on the different between the two, the argument usually goes that the former is a more nebulous concept which has general legal protections and responsibilities, while the latter is a specific academic protection within the Education Act which allows researchers to pursue things which might be unpopular, unfashionable, or controversial.
But academic freedom is often stretched to mean a universal right to pronounce on lots of topics. After all, there is no clear beginning and end to intellectual enquiry.