Required documents to extend Entrepreneur visa

[Maran]

Can you tell someone who knows very clearly required documents to extend entrepreneur visa for whom applied as in country applicant for their intial application.
I understood about
1.money should be invested at the time of application and it should be certifiedby the recognised Accountant.
2.Two full time employment for 12 months for UK settled workers.
3.company tax bills all ok for

......but what is that ,should I register as director with HMRC for tax if I had already shown me Director of my company for my initial application.my one limited company and have unique number.
Practically related docs to extend the visa different to
1.entrepreneur who applied as incountry applicant.
2.entrepreneur who applied & got visa from abroad.

Should 1st category need to register before 6 months of specific date.

Please someone help me.