I am Indian citizen. I was granted TIER 2 visa on 02-02-2010 but entered UK on 04-04-2010. On 15-03- 2011 while in UK, I changed to TIER 1 visa. I am planning to apply for ILR. What is the earliest date I can apply for ILR? Is it 28 days before 02-02-2015 or 04-04-2015?