My wife will be applying for ILR very soon, all language and LIUK tests are completed. My wife entered UK on a spouse visa before July 2012, so old financial requirements of being able to support each other with out recourse to public funds apply.

So my query is, as Im self employed what are the necessary financial supporting documents required ? My wife is employed so she has payslips and bank account statements as evidence.

Will taking 12 months bank statements and latest self assesment tax calculation (SA302) suffice?

Im reading about un audited accounts, proof of NI class 2 contributions etc being used as supporting documents for self employmnent.

Your latest SA statement, not your return, but the statement from HMRC, and bank/building society statements, all personal and business accounts, should suffice.