Form FLR (M) - Does partner have any children in the UK?

Hi, I am struggling with whether I should be answering Yes or No to partner having children in the UK. He has a few children but are all are over the 18. Some of which he does not have contact with. When I clicked Yes it was then asking for lots of details such as their passport info, utility bill confirming the other parents address etc.

I would really appreciate any thoughts.

Many thanks in advance!

Answer should be yes

As it asks for the childrens passpost info, travel history, address of their other parent, copy of their utility bill, the childs extended family in the UK etc

What do we do if we don't know this as they are mandated fields?

As the children are adults I am struggling to see why they need this information.