If you believe that they have not supplied you with all data in response to your SARN then send a letter to the Information Commissioner formally requesting an assessment.(posted 8120 days ago)The IC web site has a prototype assessment form which you can download if you wish. Using the prototype form ensures that you don't miss out contact details etc..
The IC should reply to your assessment request with a reference number within a week. I would suggest that you send a copy of the IC reference number letter to the solicitors and Halifax stating that you have made an assessment request under the DPA, and until they supply ALL data matters can't proceed further. (But I am not a solicitor so you may wish to confirm this approach with somebody else)
You must supply copies of your letters to the IC with your assessment request letter, letters to the solicitor and Halifax asking for all data, and copies of all their letters to you in response. You need to prove to the IC why you feel that you have not been provided with full details. The more proof, the better.
There is no charge for this by the IC.
The IC is currently running with a processing delay of 8 to 10 weeks for assessment requests. Since the change to the DPA they have been swamped with such requests.
You can telephone the IC and ask for the consumer help desk to discuss your assessment request on 01625-545700. The IC is very helpful, but they are also very busy and at times you are placed on a very long hold waiting to speak to somebody.
Good Luck.