Firstly decide which codes you will be following:
1) The 2007 Codes require auditor’s certificate or similar certificate issued by an accounting officer or verification agency.
Comment: Get your accountant to write a letter confirming that your revenue is below the threshold.
2) The Amended Codes require a sworn affidavit on an annual basis confirming the annual revenue and the level of black ownership
In all cases the Codes require you to have suitable evidence supporting your status, such as audited financial statements, or other financial information that completely proves your letter or affidavit.