Hello Rao
5 years p60 is a proof you were economically active. you need to show only 12 months salary slips and proofs.
dont have to show degree since used in last extension.
My case was similar to yours. got ILR peo croydon 27 oct 2014. good luck.

passport with visa stamps is what they look for.

you need bank statements, salary slips, p60, letter from employer. All originals.
Keep it simple. if you have gained enough points from one source show only that.

The account(joint with my wife) where my salary goes is always in debit.
but i have another account which always had the maintenence funds available for atleast 3 months. will the negative balance in my salary account affect my TIER 1 application if i send my bank statements. plz advise.
thanks