Doesn't really matter as long as its BPS accredited and you get good grades.
What will be important is the work experience you get alongside your degree, and how you compare when it comes to applying for Trainee Forensic Psychology posts after you graduate.What may give you an advantage is a course that has a built in placement year, and you get a forensic placement.
In terms of good Forensic Psych departments (for postgrad), Liverpool and Surrey have well renowned Stage 1 courses (MSc) and Birmingham has a Stage 1+2 DForenPsy course that I have heard good things about. That's all years away for you if you are still doing A-levels though.