EE : No lastname in former name

In my education documents and previous passport, I only had first name (NO last name).
Later I went thru name change process and applied a new passport with first name and last name.

Now I have got an ITA and while submitting the details, I have to enter any former names.
But while entering former name I notice that both first name and last name is mandatory.

It does NOT allow me to leave the first name blank as mentioned here:

What to do in this case? How to enter the former name? Please advise.

I dont think name change means adding missing last name.

How did you add name , I’m facing same issue ?

Can you tell me what you did as I’m facing the same issue . Thank you.

We faced the same issue for my wife’s name.
We wrote a letter of explanation for “one and the same” name and mentioned that FirstName is same as “FirstName FirstName” and used the first name in all places as first name AND last name.

It was accepted. I hope this helps.

My wife did this (added her last name) and we did not mentioned the previous documents anywhere during submission.