Prior to August 2017 all Priests of the Archdiocese are under strict instructions not to write references to support applications for any school, Catholic or non-Catholic. The only information that could be given was details of Baptism.
There was a change to the guidance in August 2017 when Fr. Tim issued the following statement
Certificates of Religious Practice for Faith Schools
I understand that the Archdiocese has revised its position with regard to these references and left it to the discretion of the parish priest. I have resolutely followed the previous diocesan policy that I should give only factual information regarding the reception of the sacraments, which protects me from the potential conflict of having to determine what is meant by religious practice and therefore I do not intend to start giving personal testimonials now. If particular schools are willing to accept others as referees, then there is nothing I can do about that, but I insist that such references DO NOT carry any form of official approval from the parishes for which I am responsible: e.g. parish letter-headed notepaper or an official stamp.