Thank you @Kal_Lam for the welcome, and for developing and maintain this wonderful resource.
Yes, that is exactly what I am trying to do. As far as I can see, the dynamic data feature works by querying a single record in the Parent project and then allowing access to the attributes in that record. What we need to do is run a query against the unique identifier in the Parent project to start with to populate the Select One options in the Child project. In the Child project, the Select One answer is then used to select the appropriate record in the Parent project so that the rest of the dynamic data attachment features can be accessed.
Kind regards,
Darren