in the bit where it asks for the date of birth of parties and any children of the family, I presume this means only children born into the family formed from the divorcing parties (or taken on as a result of the family being formed) and should not include any children that belong solely to a partner of a new relationship.
Not sure that I have worded it right, but in simple terms should it include only me, STBXH, our DS and not the children of STBXH new girlfriend by 2 other men and not STBXH.