When can I get my ILR

I came to the UK as a dependent (spouse) of a student in 9/99.

I found a job and worked for two years.

My leave to remain as a student spouse was extended until 21/10/2004.

Later, whilst continuing to work in the same job, I applied for a work permit which was initially approved on the 5/7/01. The letter told me that I can work and that my WP has been approved for 60 months. It also stated that decision on the extension of my leave would be received later date and that if it was refused then I need to stop working.

I waited couple of months and on the 13/10/01 I received a Work Permit and a letter ICD0358 saying that my Leave to Remain was extended until 11/9/2006.

When is the earliest day I can apply for ILR?

28 days before the 4th year anniversary of the date on the ICD0358 or 13 OCT 2005 whichever is the earlier.