When we applied for our 3 year residency (due to run out in 2015) the authorities were satisfied with copies of letters from UK Pensions Department detailing the amount of state pension both my husband and I were entitled to receive each month, as proof of being able to support ourselves here. We didn't have a Turkish bank account, still haven't, nor do we want one, but at least we have a year to sort it out if it is a requirement for renewal. Unless of course the Turkish authorities move the goal posts again.
I cannot understand why they seem determined to make life difficult for ex-pats, after all we're no drain on their system, pay our own way, and provide much needed funds for the local economy. We're becoming more and more disenchanted.