Nick Baty wrote:...it's not the E&W bishops who are making the rules. These come from ICEL. (Ultimately from GIRM.)
Found it – GIRM 393:
Bearing in mind the important place that singing has in a celebration as a necessary or integral part of the Liturgy, all musical settings of the texts for the people’s responses and acclamations in the Order of Mass and for special rites that occur in the course of the liturgical year must be submitted to the appropriate office of the Conference of Bishops of England and Wales [Secretariat for the Liturgy of the USCCBs] for review and approval prior to publication.
This is broader than what the Guide for Composers is saying.
A text like Our Father is public domain and no copyright permission is needed if it is published as a separate item – as part of a complete Mass (whatever we understand that to be) it would fall under the jurisdiction of the bishops' panel. The same would be true of of the Holy. The new version was originally ICET, I think, and has since passed to the public domain. In this case, a publisher could, technically, publish a Holy without clearance – but they wouldn't be able to publish the rest of the acclamations. However, CTM and the Guide for Composers both stress that "any musical setting should respect and enhance that unity and therefore provide a complete set of acclamations (Sanctus, Memorial Acclamation and Amen)".
So we really do have a loophole here. Unscrupulous publishers can do what they like. Those smaller set-ups which care about the liturgy can't.