You need to go back to elementals. Your main starting point would appear to be Henry's bible and the first thing to consider is when the information was added to the bible and by whom. Obviously the writing cannot be earlier than the publication date of the bible, and in most cases the older entries have been entered at one time, in the same handwriting, with the same pen and ink. If the bible was printed in Australia the earlier entries were already "old news" at the time it was purchased. Sometimes the oldest entries have been triggered by some event (probably the last in the opening handwriting) and if this happened to be the death of "Henry Thomas Broadwood" what is written is can only be the remembered part of what he told his wife (if still alive) and children. Such information may not be accurately remembered. In a few cases someone has done some research 100 years later and written it into an old bible - and the results are no better than their incomplete research. So when you have an old bible the first thing to do is to try and date when the entries were made, and possibly who by.The situation is complicated because many people who went to Australia wanted to live a new life unencumbered by the problems they had left behind in England. In most cases where a father's occupation was given in Australia as farmer the reality was that he was a poorly paid agricultural worker on someone else's farm in England. However in Australia no-one is going to check and it is easy to describe how his father (in reality his father's employer) ran the farm. So family traditions tend to be upwardly mobile.There may be cases where it was "diplomatic" to change one's history. It would be interesting to know how many bachelors married in Australia when they had already had a wife and children in England (or in one case I have investigated, in New Zealand). If they were illegitimate they often invented a father when they got married. In some cases there may have been a very good criminal or financial reason to make even bigger changes - for instance see "What did your Ancestor call himself".
Of course most family documents are reliable - but in some cases the original may not have been completely truthful, and in some cases the "evidence" may have been added years later.