The Information Commissioner has great difficulty in investigating complaints about non-compliance with Subject Access Requests when the complainant is unable to provide any evidence that the request has been made.
You are strenuously recommended to send all Data Protection Act disclosure requests at least by recorded delivery.
If you have to make a non-compliance complaint you should accompany your complaint with a COPY of the recorded delivery receipt together with COPIES of any other evidence which you might have that the bank were sent or received your request.
The current turn-around time for Information Commissioners Office complaints is approximately 5 weeks due to the high level of complaints being made.
The Information Commissioners Office will be implementing a new complaints system which may allow complaints which are accompanied by suitable evidence to be dealt with within 10 days.
Complaints which are not accompanied by evidence will continue to be delayed and will stand a considerably smaller chance of being resolved in the complainant's favour.
You can download a complaints form either as Word doc or as a pdf