Hello
My gt gt grandmother's 1st husband was in the 51st Regt that arrived in Tasmania 1838, as mentioned the Regiments were fragmented, I have found the 51st arriving on several ships and the soldiers, their wives and children are never named, unless he was an officer of course.
When my soldier was pensioned out of the army he was employed by the Government as an Overseer. I engaged the Tasmanian Archives to do a search on him and I learnt a lot through their work.
It is an avenue you might like to think about using. It may or may not help, but it's worth considering.
Regards
Maeeye