OP, I've not read all the thread, but I got up to the bit where you said you would like to retrain, but you would lose your JSA.
There are now grants available for age 24+ students in post compulsory education courses, so further education etc (I don't mean the grants that go to students studying degrees). I'm not sure if you would qualify for this to retrain as a legal secretary, and if you do, whether it would be enough in replacement for the other benefits you will presumably receive due to your DH also being out of work and with you having dependants.
It might be worth going to see somebody at your local further education college. Going by what we have at our college, we have a dedicated 'student finance and support' person who advises students on their fees/grants/loans etc.
Like I said, I'm not totally sure because I work in higher education in an further education college, so I just saw something in our weekly newsletter, but I didn't get anymore details because it's not applicable to me.
Either way, good luck with your search for work and I do hope that you get some positives from your 'slave work experience'.