I think you might need to define what you mean by ‘counsellor’ because lots of things might fall under that heading but be quite different.
I am not a ‘therapist’ in the sense of being a psychotherapist, but trained in a similar modality. I think most people charge in the realm of £50-100 an hour, depending on the type of therapy, region, experience level.
Keep in mind, that isn’t like £50x8 hours of work a day. I personally wouldn’t see more than 4 clients a day, probably. You will spend a lot of time on admin, marketing, accounts, initial consultations (which are free). Overheads can be relatively low if you work remotely via Zoom, which is the norm in my field. Less so in more traditional therapeutic approaches, in which case you’ll need to rent a private office space or use a co-working therapy room set up, which can be £10 or more an hour. Then insurance and professional memberships and continuing professional development.
For traditional psychotherapy and similar, you also have to pay for supervision and your own therapy too.
I think it can be hard in those fields to make a decent income, but easier in more holistic or less traditional approaches where there is emphasis on professional development but less on personal therapy. I do know therapists who earn £40-90k a year, working from part time to very full days seeing 8+ clients.