tier 2 dependent visa validity after main/other dependant moved to ILR

Me and my wife got our ILR last week. Thanks for many of the posts by others which helped in me preparing the the documents.

I was in Tier 2 general and my wife and our daughter were my dependant holding tier 2 dependant visa.

We have not applied ILR for our daughter as we were thinking of directly applying Citizenship through MN1 application as she was born here in UK and now 4 years old.

We have a trip planned in December, so wondering whether her tier 2 dependant visa (valid until June 2019) will still be valid?

Could you please refer to some official documents which says so? In case if we need to show it in border control officer while entering in to the UK after our trip.

I have seen some other answers in the forum but they are not of exactly this situation or without any official proof.

It is still valid provided you got ILR based on Tier 2 General.

UKVI know the rules. If asked, which is unlikely, you simply state she is UK born and will be registering her as British on form MN1 under section 1(3) of the nationality act.