ILR for Tier 1

[n_dinesh]

Hello All

I am applying for ILR in few weeks time and i am in process of preparing all the documents. I am currently holding Tier 1 HSMP visa.

I have couple of questions
a) Do I need to submit P60 for all 5 years ?

b) Will Pay slip for last 12 months suffice ?

c) Do I need to obtain a employment reference letter from my current employer ?

Thanks

Regards
Dins