Deepi9, this forum is mostly used by students hoping to study at US universities. Very few people are familiar with different degrees and career opportunities in the UK. You might get better answers in a forum for British students, such as The Student Room.
The first obvious question you need to ask yourself is which population you want to work with. Adults or children? High-functioning or low-functioning populations? (Edinburgh’s department follows a person-centric and psychoanalytic approach, which is most often used with high-functioning adults.)
Of course that decision isn’t final yet. An MSc alone doesn’t qualify you to work as a counselor and you’ll have one more opportunity to change focus when you pursue your next degree. That said, if you have never worked a full-time job with children, I’d recommend you do that before you pursue a degree in child and adolescent mental health.
How so? I am not familiar with counseling education in the UK. I do know that there are different educational paths for clinical psychologists in the US (a research-oriented PhD vs a practice-oriented PsyD) and that the career trajectories are largely the same. The PhD has the one significant advantage that there may be funding available, whereas PsyDs are self-funded. I am having a hard time imagining how the two UK options could be so far apart that it’s not even worth discussing the similarities and differences. Maybe you could explain?