NHS Student Job

Hi,
I have recently decided to change my career and applied for a job in the NHS which would require me to attend university and placements. Job advert stated it is a full time post - 37.5 hours per week.

My contract states I would be paid for my time in placements but nothing for the time spent while attending university.
In the contract they only stated how many hours of work i would be paid for the next two years. When i calculated it works out average of 19.5 hours per week but in reality I am expected to spend my all spare time studying + attending university.

What would I be classed as? Student? Part time? Full time?

I also have a 6 months old daughter and partner currently receiving maternity allowance. the student salary for the first year 14.5k , so when i type in my details to the calculators it looks like i am making 14.5 k for only working 19 hours a week. Surely i should be classed as working full time as my employment requires me to attend university. (they also wont pay the tuition fees!! and the course itself is not eligible for NHS bursaries on top of everything the course being a postgrauate diploma I cant apply for student loan etc.

I am trying to see what help would be available in terms of working/child tax credit.

Thanks for your help in advance