I don't believe there's a free online version.
What’s the name of your current prayer book?
Recently a ton of liturgical material has been released online, so one can now freely access the best and most well known translations of Orthodox liturgical texts such as the Triodion and Pentecostarion, and now, in the English language, all of the Byzantine Rite liturgy is now online, in addition to all Roman Catholic liturgy according to the Dominican, Sarum and Tridentine (16th century, the revisions under Pope St. Piux X, and the less well advised revisions under Pope Pius XII and John XXIII and the final obscure mid 1960s revision under Pope Paul VI before the reforms of the Concilium (which might not be fully freely available; I think there are parts of the Liturgy of the Hours, for example). However, it is even hard to find a complete Latin, Spanish or Italian missal or breviary of the Mozarabic and Ambrosian Rites, and since both of these were changed (especially the Ambrosian, which was modified almost as much as the Roman, and wound up with six Eucharistic Prayers rather than four). Additionally, as far as I am aware the Carthusian mass is available online in English but not the full Carthusian missal or breviary (the Carthusian and Dominican rite masses look a lot like each other, the only difference being the language is, as one would expect, slightly more penitential in the Carthusian and slightly more cheerful in the Dominican, but the two are more closely related to each other than to the Tridentine use - they represent earlier standardizations that were done for different reasons, from the era before the Tridentine standardization that marked the end of most regional uses (except for those of Lyon, Cologne, Braga and one or two others; the four English uses of Sarum, York, Hereford and Durham having been forced underground at this point).
Recently St. Bartholomew the Great did Candlemas in the Sarum Rite. I would be very interested in hearing a mass in one of the other ancient rites; a York missal translated into English along with interesting information on the York system of liturgical colors (which were limited to white, black, yellow and red, which is still more than the Mozarabic, which uses white vestments only, not unlike Coptic monasteries).
Thanks to the efforts of members of both of the two jurisdictions in Malankara (which exist in parallel like the two Armenian Catholicoi, but unfortunately are still in a schism, albeit one that is fortunately not the result of the Soviet Union having annexed Armenia, which was the immediate cause of the previous schism between the two Armenian jurisdictions), there is now a workable amount of Syriac Orthodox liturgical material. But only 14 of the 86 anaphorae (Eucharistic Prayers) are easily available in English, and only the abbreviated propers in widespread use as opposed to the entirety of the hymns found in the Beth Gazo (Treasury) such as all of the translated Greek Canons and the Syriac Canons (Eniyono, plural
Eniyoneh) has not been made available. Likewise, we have the whole Maronite rite post Vatican II, but not the historic pre Vatican II rite.
Thus only six of the 50+ Maronite anaphoras (many of which are basically the same as their Syriac Orthodox counterparts, the main difference being at some point, presumably after the Maronites resumed full communion with Rome several centuries after their schism with the Syriac Orthodox, the Theopaschite Clause was removed from the Trisagion Hymn, and perhaps they added the filioque; I don’t know, but it is the case that avoidance of the filioque was mainly limited to the Greek Catholic / Byzantine Rite Churches.
additionally all of the Coptic Rite is available through the Coptic Reader app, but getting all of the material costs about US $40, but this was available some time ago, and most of the material is also available for free, but the Coptic Reader is worth the money since it arranges the liturgical propers automatically, whereas otherwise one has to know the Coptic equivalent of what the Orthodox call the Typikon, the Syriac Orthodox and Assyrians call the Hudra (Khudro in West Syriac) meaninf Cycle, the Armenians call the
Donatsuyts meaning Directory and the Western churches call the Ordo and in the Sarum Rite it was apparently called the Pie, based on this quote from older, more Cranmerian editions of the
Book of Common Prayer:
“Moreover, the number and hardness of the Rules called the
Pie, and the manifold changings of the Service, was the cause, that to turn the Book only was so hard and intricate a matter, that many times there was more business to find out what should be read, than to read it when it was found out.”
However by the 19th century the needs of the High Church community exceeded the rubrics in the BCP concerning liturgical propers, which led to the Directorum Anglicanorum and the Ritual Notes, and the inclusion of complete Paschal services in the 1979 Episcopal BCP, which the 1994 Anglican Service Book made entirely available in English (following a rubric that expressly allows doing this), as much of the additional material such as offices for midday prayer etc was only included in the contemporary language Rite II, as it was envisaged that parishes that preferred Rite I would simply rewrite them. The Anglican Service Book is completely available online as are Ritual Notes, the Directorum Anglicanorum and all Episcopalian editions of the BCP are in the Common Domain (apparently this is also the case with the 2019 ACNA BCP).
Given this, I would not be surprised to find the Australian book, but I can’t remember the name.