ask for the letter as per the bank's format. For all missing details get stamped account statements(6 months). Write an LOE that bank couldn't provide the reference letter as per CIC format.
Highlight any significant credits in your account (if any) and upload proof of source of those transactions
If you are having funds in fixed deposits or as bonds, you can use the certificates copy and attach a business card from the bank manager.
Take some print outs from cic website on proof of funds and show to the manger and ask him to provide a letter on the letter head or on a plain paper with seal and attach a copy of his business card also
Take your last six months account statement get it stamped from the bank and attach a copy of bank manager's business card