some links for National Insurence Number:
Applying for a National Insurance number : Directgov - Money, tax and benefits
Jobcentre Plus
In order to apply for NI nr. U have to make an appointment with the local jobcenter plus.
They will need proof of address from UK; proof of identity ( passport) and maybe a letter from the employer ; anyway they let U know about the documents required.
all the best!
Hope the courses are still going to run this year ! Otherwise why bother to recruit
!