I guess it depends on how long it is until the final hearing and how serious/disruptive the breaches are.
As a minimum action it would make sense to carefully document the breaches (with evidence wherever possible).
You might choose to write to your ex or their solicitor to inform them that you consider the agreement to have been breached that you will be taking advice on the appropriate enforcement action. (ie you dont necessarily go straight to form C79 without this kind of pre-action letter).
Even if you don't try to enforce - by documenting the breaches you can present the problem during the final hearing with the aim of influencing the outcome, for example improving the wording of the final order to better deal with the high likelihood of non-compliance.