Hi there,
Some thoughts...
I have had a quick look at other threads you have posted on, and notice that you are based in Australia and also that the surname TANDY is part of your family tree via your grandparents, James Gibson and Louisa Jane TANDY who were married in 1910 at the All Saints Church in Croxley Green, UK.
http://www.rootschat.com/forum/index.php/topic,568493.0.htmlMay I ask some questions please about TANDY and NSW and your research in NSW for him. You mention you have been searching for lots of years for him.

Do you think there may be some connection to your grandmother, Louisa Jane TANDY? Perhaps via earlier members of her paternal line?

Do you have any thoughts about who and/or when they may have migrated to or at least visited NS Wales? What names or other clues has your long standing research for this elusive Mr Tandy turned up please.

Where have you looked for him, and when were you looking ? Is it possible that those places have added to their archival collections since your most recent contacts with them?
I am somewhat concerned about his actual surname, and I realise I have addressed this previously on this thread,
but how certain are you that his surname was TANDY. May I again pose the question .... Is it possible that it has been mis-transcribed.... the Old style capitalised letter “T” is also part quite a number of of the Old style capitalised letters and has often been confused with the capitalised Old Style “F”, “H”, “K”, “L”, “S” “X” .... The entry on the NSW BDM mc will be from the typed ECR certificate, but the 1860 d.c. should be a digitised image if it is the real deal certificate. So it is possible that you have only that one example of the actual use of that surname in respect of Bertha. As you have noticed, there’s not much around in the currently available NSW online indexes for any likely candidates for Bertha’s Mr Tandy. So, perhaps he was Mr Handy/Hendry/Kandy/ Landy/Sandy/Thandy/ etc.... rather than Mr Tandy.
I also continue to wonder if George Glover was actually Bertha’s father. And that would be a further reason for seeking Bertha Coxhead’s d.c. I must admit I am somewhat surprised that you have commented that you have been seeking this Mr Tandy for lots of years, yet you have not yet obtained that d.c. However, I am sure each of us has our own ways of conducting our own family history researchings.
On one of your other threads,
http://www.rootschat.com/forum/index.php/topic,568306.0.html I can see where you have Bertha as born about Nov
1883 (
edit JM typo, thanks Caryn for the heads up, it should read 1833 as per replies # 35 and #36), Wittersham Kent to Amelia Gorham and George Glover, and that an experienced RChatter has quite recently found her christening as 1 Dec 1833 under the name Bertha Gorham, with father un-named, and pointed to a possible link to a submitted tree.

Have you tried to contact that submitter with the view to seeing if they have further information about Bertha’s marriages, particularly the one for Mr Tandy?

Is it possible that at sometime after Bertha’s mum died, and as Bertha was growing up that she was returned to her UK Gorham family where she may have married that elusive Mr Tandy?

Have you researched her Gorham family at all? Perhaps Mr Tandy was not ever in NS Wales, perhaps Bertha returned to NS Wales after he died/disappeared from a marriage with her in the UK. Perhaps if she returned to the UK then in the UK she was known as Bertha Gorham...
Afterall, Bertha’s connection to George Glover may well be that of a step child, and thus her connection to his second wife may quite remote. Perhaps as Bertha grew up, she became distant from George and Herriot. I notice you have not located George and Herriot. Also I notice that you have not actually confirmed that it was Bertha, and her younger bro who were on the Augusta Jessie... Are you sure that is the 'right' George Glover? It seems likely, but how sure are you?
Hope you don’t mind my expressing these thoughts, and that you are willing to share your thoughts in return.
Cheers, JM