Standard Visitor visa with only one name on passport

[vinit_tyagi]

Hi,
I am on tier 2 general visa. I need to apply standard visitor visa for my mother. She has only given name on her passport and family name is blank. I don't know how to enter it in the visa application.
Last time we applied was in 2015 and it was a different form which said if you have got only one name then enter it in both the places. Now they have changed the application form and there is no guidance how to enter names if you have got only one name.

Does anyone know how to fill in the form in this case.

Thanks,
Vinit