Supporting documents for T2 General Leave to Remain

[raju869]

I am currently on T2 General, and got an offer from a T2 Sponsor company for a research job (offer 35k). They have before sponsored people from India on T2 General, and those were applications for people residing outside UK.
I am inside the UK since the last two years on a T2 General visa, have enough savings to show maintenance and graduated from Bristol University, so even English requirement is not a problem for me.
This job is not in the same SOC code, since I am a web developer now, and this new role is data researcher.

My new sponsor is asking for help on how to start the visa process. They say there is very little guidance given on UKVI page about people who are switching from one T2 General to T2 General.

I would like to know the following from you experiences please:

1-What documents do I need to give my employer to Issue me a CoS?
2-What documents do I need when I am making the application for T2 General Leave to Remain?
3-Do I need to prove maintenance requirement ( I have enough savings) and English requirement (I am graduate of Bristol university).
4- Can they issue me an unrestricted CoS? What is the way for them to issue an unrestricted CoS ?
5- I will not hand in resignation till my new BRP arrives, so till then how do I tell my old sponsor that I am planning to leave? What legal documentation under UKVI laws do I need to give them?

Thank you very much guys!

[iworker]

1. the process for issuing cos for people inside uk is much more simpler and easier. Ask them to apply for 1 allocation of unrestricted cos using the SMS system. Once they have the cos allocation, they can assign the cos to you in 15 min.
2. to assign the cos, they will need your personal info like name, place of birth, passport number, NI number etc.
3 NO
4 yes. as above
5 Do nothing, say nothing till u have the new visa.