My Tier 1 Entrepreneur Visa Ext has been approved after 10 months without Interview


My time line is;
Application: 14/12/2017
Biometric received and done: 21/12/2017
Approval Letter with documents: 24/09/2018
BRP Received: 25/09/2018.
No Interview
No MP
No Telephonic inquiry
No email.
Thank you and good luck to all

QUESTION:
Dear gurus and members, my son was born after the application and I want to apply for his visa, can I apply for his visa through "premium service" ?
Thank you