Yeah so i can get that in my second year for 3 years even if i'm registered on a programme. In addition, could I do 1 year of a phd and then apply for department funding for the other years?
With the AHRC at least, if you apply in your second year (for your third year) they'll only give you one year's funding. It's not for three years from the date when you apply.
Usually after some months of research you might be able to improve the definition of your research topic and in this regard that can make your application stronger when applying for research councils funding.