Yea, october 2011 bank statement is fine. In SET(M) applications, they are really not out there to catch you out on a technicality. You just have to provide proof that establishes you lived 2 years as spouse. 6 items requirements is in guidance, not a rule.
I am sure you have all the bills/documents coming to your address like any other household in UK. ie water, electric, bank statements, tv license, council tax, phone bill etc. You will have no problems.
regards