A very good alternative to playing mp3 files in your browser or in the Windows Media Player is the program VLC Media Player, which is downloadable free of charge from the website:
The Chorale has purchased licenses for permission to use John Fletcher practice recordings. Some of these licenses are still available free to Chorale members. If you would like one, please speak to alto Vicky van der Luit, who has kindly provided the following information:
There is a free John Fletcher option:
https://johnfletchermusic.org/rossinig-petite-messe-solennelle/
Chord Perfect seem to have it all for free on YouTube with voices (much nicer!) but you have to scroll through everything to find your part for the bit you want to sing (at least I haven’t found another way to achieve it): https://m.youtube.com/@Chord-Perfect/search?query=Rossini%20petite%20messe%20solennelle
Chord Perfect also have the Kyrie, Cum Sanctu Spiritu and Agnus Dei available for free on their website here (online only, no download option): https://www.chordperfect.com/gioachino-rossini/
Or you can pay $10.00 at the same link for all the parts.
Files of various editions are available here but I haven’t had time listen to these as it required a midi player - I will try to do so before term starts: https://www.learnchoralmusic.co.uk/Rossini/Petite-Messe-Solennelle/petite.html