Family law - Parentage/paternity

[Flipper187]

Hi. Im currently looking for advice for my pal. Hes looking to prove parentage for his exs 9 year old. They had an affair. What im wondering is... in Uk law or even the courts is there a time limitation on challenging the parentage of a child. His ex has her partner named as the father on the birth certificate. Also can she legally say no to a court ordered dna test? What will the courts take into account if anything.

Has he left it to late?

thanks guys