I don't think that's going to have any long-standing relevance to your case. What you're attempting to show the Court is that the other parent is prioritising money over the children, but I think you'll find the Court less willing to adopt your point of view as fact.
Consider it objectively.
Say Parent A has unilaterally decided to withhold the children from Parent B indefinitely and for invalid reasons.
Parent B tries and tries and tries to negotiate an outcome without involving the Court, but to no avail. So, Parent B engages a lawyer and commences proceedings to see his/her kids again.
The Court finds no valid reasons for the children not to spend time with Parent B, and orders the children recommence the same pattern of time with Parent B as interim orders.
So, Parent B is now seeing the kids exactly the same as he used to, except now he also has a debt in lawyer fees. Both Parent A and Parent B stand to lose significant sums of money if the trial goes ahead, so it's in the best interests of the child to get out of the Court system and save all of those funds for the children.
However, had Parent A been reasonable to start with, Parent B wouldn't be in Court.
So, what does he do?
He offers to agree to the interim orders as final orders, provided Parent A compensates Parent B with some contribution to the unnecessary legal fees imposed as a consequence of Parent A's unjustified and unilateral actions.
Would you say that means he doesn't care about the children? Probably not.
See, unless they explain them to you, you don't know the reasons as to why a 'without prejudice' offer was made, but you're asking the Court to assume it's because the other parent doesn't really care about the kids. Even so, it has nothing to do with the children's best interests - a 'without prejudice' offer isn't going to cause harm to the children, nor is it going to impact their relationship with either parent. Including that kind of thing is basically just saying, 'See? Look at what a jerk the other parent is,' which never goes down well with the Court because it's petty and it's derogatory, neither of which are characteristics the Court likes to see in a parent.
With that said, I can't predict what the Court will do. I just think you should consider carefully whether this information is relevant, or if it's just an attempt on your part to twist something that happened so that it suits your narrative, even though realistically, it probably doesn't.