Hi, a degree in epidemiology will in my opinion be more beneficial as compared to a course with a narrowed focus on psychiatric epidemiology as far as career prospects outside academia are concerned. However, if you are envisioning a career in mental health specifically, the MSc Course jointly offered by King's and LSHTM might sound a better fit. Also, this course is quite highly ranked in the UK and both these institutions bring their unique strengths to it (overall reputation, menu of specialized courses, faculty expertise, etc.). Having said that, if cost is a major deterrent, you might as well choose Bristol over London, especially if the MSc course in epidemiology offered at the University of Bristol is of good repute. Ultimately, the choice is yours and I'm sure whatever you decide in the end will only usher you towards a successful career in and outside academia. Good luck and well done in thinking through your choices!