Tier 2 to ILR Help Please

[sambit2017]

I am new to this group and not sure how to post a query.

I am in UK on a tier 2 general visa. My COS was assigned on 13/oct/2012 with expiry date on 13 Jan 2013. My original work dates are - 30 oct 2012 to 29 oct 2015. It was extended for another 3 years and it is now valid till september 2018. I am living continueously since that time. Only had taken a total of 19 unpaid leaves in the year 2015.

My original Tier 2 visa was stamped on 27 Nov 2012 but I started my initial work on 23/dec/2012 (after around a month of the visa stamp date).

Can someone suggest when shall I be able to apply for my ILR at the earliest and also if the unpaid leaves will be a problem.

Many thanks,
Sam