CAFCASS correspondence / disclosure

Hi All,

Am I right that during Children Act proceedings, there is an onus on both parties to disclose correspondence with CAFCASS, as an office of the court? My ex is writing to them without me on copy then referring to those letters in joint meetings, am I within my rights to bring up the lack of disclosure if they continue to refuse to provide me with a copy of what was sent? I've looked through the FPR rules and it seems a tad vague.

Thanks!