Thank you Judith, that is a very kind offer but I wouldn't want to impose on you. I intend to visit Yass myself next time I'm back in Australia and I've been in touch with the parish office there and apparently they will conduct research for a "donation" of $50 but it can take up to three months. However, if you're ever in the vicinity and you'd care to make an enquiry, that would be greatly appreciated.
I agree with Sue and Wivenhoe that there are a lot of undocumented assumptions and I've been trying to sift through these over the past couple of years. I've been involved in academic history research for the past forty years so I do understand the importance of primary sources.
The first assumption I tested was the rather absurd notion that Ellen was aboriginal and I've proved that to be false with my mtDNA test (if, of course, she was Mary Ann's mother). Last year I also exchanged a series of (exacerbating!) emails with the person who created their find-a-grave entries, trying to nail her down on the sources of her information. I also agree that these ancestry sites are riddled with errors which are just copied and pasted without checking their authenticity.
Two of my cousin's did a lot of research on this side of the family 30 or 40 years ago and I think that a lot of the information surrounding Michael Delaney and Ellen Collins originated with them. Unfortunately, one of those cousins has passed away and the other is very elderly, so it's difficult to verify their sources.
Having said that, I do think that the evidence of the BDM records together with Mary Ann's obituary and Michael's death certificate, while not conclusive, does suggest that Mary Ann Delaney (Boyd Hendry Powell) was the daughter of Michael Delaney and Ellen Collins.
As I mentioned earlier, I hope that an autosomal DNA test might shed some more light on the subject.
Thanks too Judith for checking Michael's death notice (which I do already have).
Cheers
Bill