Current Visa Expiring Pending MN1 3(5) Registration

[Mish79]

I applied for my 3 children to be registered under Section 3(5) as their father is a British Citizen by Descent and our family has been in the UK for almost 5 years.
The children are in the UK as dependents on my AV which is due to expire on 1st December.
Where do we stand if we have not had a decision regarding their registration through prior to their visas expiring? Would we then need to apply for ILR when I apply, or would they be allowed to stay in the UK and wait for their Citizenship registration?

[CR001]

You could have registered the children once the family had been resident for 3 years.

Once their visa expire, they will have no legal status in the UK.

When did you apply for them?

[Mish79]

End of June but only did biometrics on 12 July. We only recently found out about this route through their father, but did not think about the implications of their visas expiring as 3(5) is an entitlement not under discretion.