One point I want to make is that a person on Jobseekers is supposed to sign off if they fall ill as they are no longer available for work. [broken link removed]
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In my case, I fell ill and claimed disability (now called illness?)benefit while I was unemployed and sent in weekly certs. (You only have to pay the doctor for the first visit, as he gets paid by social welfare ).After a period , I recovered and was available for work again but of course was still unemployed.
For the purposes of my BTEA, I think they included all my unemployed period along with my sick period as one continous time period but do not include the sick period for the purpose of calculation your total time for cutting off your unemployment.(52 week rule)
The main thing is that I was fully recovered and was ideally signing on again for 3 months prior to claiming BTEA and also be in reciept of unemployment (now called jobseekers) payment before the school registration date (this may be a week or two after the start dateof your course). Incidently, I found the social welfare officers very supportive and helpful in my case. Citizens info and AEGIS are also helpful.
Incidently, try to visit some of the universities (open) 'days' if you can as its really important to pick the right subjects and some give special talks to mature students. However, they will usaully not discuss grant or social welfare problems. Some universities are very flexible, especially in their BA programme and allow subject changes within the first few weeks.
I am saying this with a caution as this was a couple of years ago and things may have changed since.