Tier 4 student visa to Tier 2 student visa

Hi,

I came to UK for my postgraduate studies for which I took IELTS academic. Now I have completed my course and have been offered a job with sponsorship. Therefore I'm applying for a Tier 2 visa.

I'm having difficulty in filling section N, which is about meeting the English requirement. Should I mention about the postgraduate degree I received from UK or my bachelors degree with the medium of instruction being English or my IELTS academic?

Also should I do the self assessment tool for English requirement ?

I have attached the link for the document were I'm finding difficulty in filling. Page number 34-38.
https://www.gov.uk/government/uploads/s ... _04_15.pdf

Any help would be really appreciated. Thanks a lot.