uk – Tier 4 dependant visa – IHS form asking for incorrect information

I am applying for a General student visa (Tier 4) for myself, and for a Tier 4 dependant visa for my wife. My wife and I are currently in India, and we are planning to travel to the UK together. After filling my visa application, I was redirected to the IHS website where I made a payment of GBP 450 and got the IHS reference number.

However, I am facing an issue while filling out the IHS form for my wife. After filling my wife’s dependant visa application, I was directed to the IHS website. This time the IHS website is requesting for the primary applicant’s “visa expiry date” under the section “The person you’re joining or remaining with in the UK”. It is a mandatory field and the website is not allowing me to proceed any further to make the IHS payment unless I fill out this field. However, I do not have a visa yet. For clarification, (1) In my visa application, I have nowhere mentioned that I am in UK, (2) In both my visa application and my wife’s dependant visa application, I have mentioned that we are travelling together, and (3) I have used the right links to apply for visas for my wife and myself.

So my question is, what date should I provide in the ‘visa expiry date’ field in the IHS form for my dependant’s visa? Can someone please guide me on how to resolve this.