Hi Diggie,
The marriage for Henry stated his name was Henry and his father was also Henry. This may have been to make it easy for the non understanding Aussies. That is the only document I have of him.
He married Anna Maria Glover in 1876 in Gawler, South Australia. His age was given as 26 there, but her age was 16 so maybe a bit of massaging of his age as well as his name! Nothing about where he was from.
The Russian Fin I have from the police notice saying he was a deserter (attached).
When his daughter (my g grandmother) married, she gave his name as William Henrique, although he was deceased by then for some years as was her mother.
So yes, his name could be Henric, Henrik and likely Wilhelm, which would account for the V in HV.
The crew list I posted above was from a journey after his desertion and arrest. I also found a 1871 UK census showing a Wilhelm Lagerstrom, aged 23, from Abo Finland on a ship's crew. Could be him, maybe he went by both names ( see snip attached)?
He died in 1885 and whilst I do not have the certificate, it apparently states this:
March 14th, 1885. Harry LEGERTHRUM, male, 35, labourer Gawler South, Phthisis. Informant Luke Henry Hinnes, cabinet maker, Gawler West.
He was buried at Willaston Cemtery as Harry Lagerstrom, in the same grave as his baby son who died in July of the same year, also named Henry William Lagerstrom.
So for ages, I have a mixed bag.
At marriage 1876, he was 26 so born 1850
At desertion 1873, he was 32 so born 1841
if that is him on the ship's crew in 1873, he was 30 so born 1843
If that is him on the UK census 1871, he was 23 so born 1848
At death 1885, he was 35 so born 1850 (the informant was not family hence the spelling of the name, so the age was probably a guess)
I have looked at the Hiski site, but to be honest I have had no luck! Maybe I am using it wrong.