I am glad it helped. It is good to be able to confirm something from the past that you know is correct.
Rydalmere has always been the poor relation to Parramatta with history groups showing little interest.
One last place you can try for a photo or information on the coach house, and the only ones likely to be able to help are the Nuns from the Benedictine Convent that owned it and lived there for 110 years.
After they sold Subiaco they moved to Pennant Hills for sometime, and then eventually to Jamberoo.
If they have anything in their archives, I am sure they would try to help.
https://www.jamberooabbey.org.au/