shall i sign off job seekers allowance?

i've just got a part time job. i got it via a 30 hour a week work placement the jobcentre/New Deal sent me on. as the job i've got is only 12 hours a week (with optional overtime), i can still claim, (even though i may only get £5 a week JSA) so i can still get help towards dental treatment, eye care and prescriptions. the downside is the jobcentre has told me i will have to complete the placement as well as working (12 hour work, 18 hours in placement), the placement includes one day a week of job search! why search for another job when i've just got this one? it seems ridiculous. so the question is, do i sign off? additional details: i will be earning £5.35 per hour, 12 hours a week. my current JSA (before declaring work) is £57 aprox a week. not sure but believe i will not get Tax or NI deducted?!?
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if you can afford to sign off then do it. i can only apply for jobs over 27hours as i live by myself and no-ones else supports me. if you can do it go for it. you will still get council tax and housing benifits if you need them as you are working under 16 hours.
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