Incorrect Dates of Case Raised

Hi all, I finally got my SAR file back today, after waiting 49 days from the day money was taken from my account, and I have a few queries.

1) One of the applications I made was in time, on the last day of the previous leave, via Recorded Mail, and I have the post office receipts to prove it. However on the UKBA database printout I got today, I noticed that it was logged as case raised on 2 Feb 2005 rather than 31st Jan 2005. I was led to believe that the date on the postmark would have been taken as the "raised" date which was the case with a few of my other applications posted out on the last day of leave. My question is whether there is anything I can do to correct this error on UKBA's part. Is it worth getting back in contact with them to get them to change that? Are the DPU allowed to alter records when presented with the evidence? This is the only gap I have for the 10 years and although I know a caseworker can use descretion for a single gap of 2 days, I would much rather for it to be a continuous 10-year block.

2) In the reply I got, there were no landing card records although I specifically asked for them in the letter I sent originally. Does anyone know if it is only an optional item? I thought they would have kept copies of all landing cards in their system.

Any help appreciated.