I'm currently about to start a full time college course in North Wales, if you apply to Student Finance Wales, you can apply for ALG, now seeing as you've been "Self dependent" for more than 3 years (you can prove this by requesting that the inland revenue send you your end of year tax returns) you will qualify for an automatic ALG fund of £1,500, as for university you will again qualify as a "independant student" and recieve the full amount of grant (£5,000 student grant [no repayment] £6,365 [If I remember right study grant again no repayment] and the rest of your study fees are in loan form but it's about £3,655 approx this you do pay back).
In terms of your JSA you will be better off speaking to your JSA advisor but be aware that you will no longer be deemed to be searching for work and as a result you will most likely lose your JSA claim.
My best advice contact careers Wales 0800 100 900 and speak to them about it.
Hope this helps.
Dave