Sex therapy is specialised type of therapy that uses a range of interventions to effectively treat sexual problems/anxieties.
It really depends. Sometimes all you need is reassurance and essential advice. Sometimes the problem is more complex, and we need a few sessions to explore.
In-person sessions cost £70. Remote session cost £60.
Sexual problems are not one person's problem/fault. They are the relationship's problem. Your partner may be negatively affected by the problem more than you - the person who seems to be 'having' the problem. I often encourage my clients to attend as a couple when possible. Of course, you can choose to attend by yourself if you prefer or feel more comfortable that way (or if you are not in a relationship).