Its not neccesary to have a degree to enter counselling but you have to build up to a diploma (level five) to get registered. The OU has a course and often the diploma course is also offered by local FE colleges. They are part time.
http://www.cpcab.co.uk/http://www3.open.ac.uk/study/undergraduate/qualification/w09.htmThe good thing is that you can take your time working your way through the levels. You are in an ideal position if you have any access to user groups to work with.
The other option is to consider a masters conversion degree (with the fees paid for by the NHS) in something like mental health nursing. They do a fast track MSc/MA Nursing (two years) at places such as:
http://www.essex.ac.uk/coursefinder/course_details.aspx?course=MSC+B76024http://www.healthcare.leeds.ac.uk/study/PG/nursing/MSC-NUR-M13/details.htmhttp://www.brookes.ac.uk/studying-at-brookes/courses/postgraduate/2013/mental-health-nursing-preregistration/There are many more. You can get funding for maintenance.
They often ask for a first degree in a social science discipline (though Leeds take any first degree discipline) but you can also present evidence of voluntary work in the field, such as you have.
There is also the opportunity to just train as a mental health nurse by taking a second bachelors first degree (BA/Bsc Nursing (mental health) after finishing your History degree. Again the fees are covered by the NHS and you can get a bursary coupled with student loan grants for living expenses. You can access all this even if you have used student finance for another degree.
Mental Health nursing can lead to specialising in counselling/therapies within the community. However you would, as part of your degree and for about six months afterwards, have to work in a clinical setting within a hospital and would be expected to work shifts. Great career though and fair pay with the opportunity to progress in various specialist directions as you go on.
Personally if it appeals I would go the mental health nursing route as there are lots of opportunities and jobs in this field, including switching into counselling.