Tier 2 Extension - Confusion about start date of previous visa

[pintokhan17]

Hi,
I'm on a T2-General visa, and am applying for a T2-General extension.

Before the T2-General, I was on a T4-dependent visa. Please see the dates below:

Expiry date of T4-Dependent - 30 Aug 2019
Application date of T2-General - 19 Jun 2019
Biometrics appointment - 3 July 2019
Application decision letter dated - 18 Oct 2019
New BRP issue date - 10 Dec 2019
New BRP expiry date - 14-Apr 2020

My contract's been extended for a year, and I'm now applying for a T-2 extension. However I'm confused what date to put into my application in "Start date of current visa"? Is it the date on the letter? Or the new BRP? My T4 ran out on 30 Aug, I'm guessing the terms of the T4 were in-place till I got the decision?

Lastly, in any future ILR applications, my 5 year period would start from Oct/Dec instead of August, as it should have been if HO hadn't taken forever to process it?

Thanks in advance.

[pintokhan17]

Hi guys,
Any advice please?

[pintokhan17]

Can anyone please advise? It's sort of urgent.

Thank you