Lead Applicant In The Nhs Surcharge.

Hello,

I am Tier 4 General PhD Student. I am calling my family to join me. I was aware that NHS has added an extra surcharge but when making the VISA Appliction online i didn't see any section for its payment.

Now my family has submitted their VISA applications without the NHS Surcharge. They were told that they have to pay the amount within 7 days online.

I registered account online at https://www.immigration-health-surcharge.service.gov.ukfor the payment of the NHS Surcharge and added my family member details.

At the application Summary page it is said that:

"You cannot add a main applicant because you already have dependants"

I need clarification that:

Am i the main applicant or my wife in this case? My wife is the lead applicant.
and
Do i need to start separate applications for all my dependent children?

An early response would be very much appreciated.

Many Thanks.