how to fill up British passport form for 1st time

[avatar16]

Hi all ;
please do we need to add the details of our grandparents on section 8 on the form for the first time applying for British passport? as i noticed on the side of the form was a notice saying you need to use section 8 and write full name +D.O.B+nationality+ date of marriage for both of grandparents while the space is not enough to do that.
any advice plz

[CR001]

Grandparents details are NOT required if you are a naturalised citizen.

Parents details are required.