You can declare yourself self-employed and, as long as you are "working" less than 16 hours/week, you can still claim full JSA. I did this for 10 months before going onto being fully self-employed and running my own new small start-up business. When I was claiming JSA, everything I earned from my self-employment over £5/week had to be declared but, of course, this can be offset against any expenses. Being self-employed for 2 days a week means that your job search activity is limited to just three days a week, so you can spend some time researching, putting together your portfolio, etc. You don't have to earn anything from that self-employment - it's literally a breathing space to get on with your own things.
Once you decide to go fully self-employed, the Job Centre will arrange an interview with the likes of Blue Orchid who will assess your readiness to go self-employed and offer free training workshops/advice etc. There is usually an 8 week period in which the Job Centre will allow you to concentrate on developing your self-employment business and don't have to undertake any other job search activity.
I can't understand why you were forced to go down the work programme route when it's obviously not going to help you achieve your goal of being self-employed.
On the downside, being self-employed is horrendously difficult but there is lots of help/advice available. My income from self-employment after almost a year, after expenses, is negligible so I receive Working Tax Credits of £53.00 until my income increases. Being self-employed is a million times more productive and satisfying than being on the work programme. If you believe in yourself and are fed up being victimised by being unemployed, do something positive to help yourself.
Just advise your local Job Centre of a change in your circumstances and stand your ground. Become self-employed (for just less than 16 hours a week for now), register with HMRC and get the ball rolling. I started my self-employment just months before I was due to transfer to the work programme. I know, despite all the difficulties, that it was the best thing to do. It's not up to the Job Centre to decide whether you become self-employed or not - that's your decision to make. By the way, I'm 60 - and if I can do it, anyone can.
There's lots of information online to help you.
Best of luck