Eligibility for ILR

I got my first work permit from 1 August 2007 but I travelled to the UK on the 1st of September 2007. Since then I moved on to Tier 1 and am on my second part of the Tier 1 till 11 September 2013.

I want to get the ILR asap, am I eligible to apply for the ILR, taking into account the Date of work permit issue i.e. 1 August 2007 or Date of arrival in the UK on September 1, 2007?

Date of arrival in the UK on September 1, 2007
If there was no gap between WP to T1G, then you can apply a max. of 28 days before sept 1, 2012.