If you intend to withhold based on the psych report, get confirmation from the psych the mother also has the report, and you also send a copy via registered post.
What happens next will depend on whether she goes for an ex-parte application or not.
If ex-parte, I do not know what happens and suggest you call the court and ask for their processes on defending against a recovery order.
Make sure you have paperwork backing up your story ready to submit in response. By sending the copy to the mother if she makes an ex-parte application she should disclose that fact to the court when making the application. If she doesn't it strengthens your case to have the recovery order withdrawn.
What happens next will depend on whether she goes for an ex-parte application or not.
If ex-parte, I do not know what happens and suggest you call the court and ask for their processes on defending against a recovery order.
Make sure you have paperwork backing up your story ready to submit in response. By sending the copy to the mother if she makes an ex-parte application she should disclose that fact to the court when making the application. If she doesn't it strengthens your case to have the recovery order withdrawn.