Tier2 to ILR - continuous residency with out-of-time application

Hi,
I will be due for ILR next month but a bit worried about one of my previous Tier2 extension applications made in 2015. My application was rejected and the decision came after my leave has expired. A new application was made and it was successful.

Tier 2 Leave till: 14/April/2015
I applied before expiry but it was rejected.

Rejection letter came: 28/April 2015
New application made: 30/April/2015
Received BRP: 14/May/2015

I was not allowed to work from rejection decision date till I received the new BRP. I have gone through many posts and found different answers. But how to count overstayed days in my case?
My case is prior to Nov 2016 rules so I should be within 28 days grace period.

Kindly help.
Thanks

It will be discarded for ILR

do I need to get a letter from previous employer saying I was not allowed to work during that time? Or would it be unpaid leave mentioned in holidays/absence letter?

No