Backdated letters - Inland revenue computer system

Dear Sir or Madam,

Please provide the appropriate documentation for the Inland Revenue
computer system that states letters cannot be backdated by more
than 7 days from the current date.

Yours faithfully,

Simon Kloot

Dear responses, FOI,

Further to your response dated 19th May, I am writing to clarify
the information I require.

Contrary to your statement, I did contact HMRC, but with reference
to the Data Protection Act. My dispute with them is that they
generated a "post dated" letter, a letter that my accountant and I
never originally received. When I took up this issue with HMRC,
they supplied "proof" of the letter which I believe was issued
recently with a date in the past.
On contacting HMRC, Mr David McDougall claimed that HMRC can only
be backdae letters to a maximum of 7 days in the past. I simply do
not believe ths.

This has led me to my FOI request asking whether letters can only
be backdated for the last 7 days on your self assesment computer
system. I need more than an official's word on this which is why I
am asking for the relevant section of your computer manual or
definitive proof.

Therefore, I am leaving my FOI request open until this information
is given and I will submit further requests in different forms
until I get a satisfactory answer.

Yours sincerely,

Simon Kloot