German ancestor brick wall

[AmyThompson]

I'm trying to research a fairly difficult German ancestor, Otto Martin Hassel/Hassell.

Otto was born in Germany around 1854 but by 1878 he is living in London and marrying Ann Elizabeth Ashton. In the 1881, 1891, 1901 and 1911 censuses he is always listed as German, not naturalised.

He lived in London until his death in 1924, never seemingly becoming a naturalised british subject yet on the electoral roles. I've looked in the national archives naturalisation records and can find no petition granted or rejected for an Otto Martin Hassel. I can't help but wonder what his position was during WWI as a German subject, but can also find no record of him being removed to an alien camp. Two of his sons were serving in the British Army in WWI.

As well as naturalisation, I can also find no immigration records or passenger lists for him arriving either (presumably between in his birth in 1854 and his marriage in London in 1878).

The only clues I have are that he is continually listed as 'German' in censuses from 1881 to 1911, with place of birth given as variations of Nünsberg/Nürsberg and Nürmberg - which I'm taking it to be Nuremberg. And also his marriage record to Ann, in which his father is listed as Harry Hassel, Surgeon.

I am totally and utterly stumped on this one, and would be delighted if anyone could help. I'd really like to trace where he was from and be able to go back a generation to Germany. This is a side of the family that would mean a lot to me to uncover: Otto's son being my nan's father who walked out on her aged 6 (in 1939...). I've only just discovered that her father died 6 months later (naturally, not WWII related), though she lived the last 79 years wondering why he never made contact as they adored each other. She had no idea he was half-German.

[gilian rowland]

AMY
You say that on Otto's marriage certificate his Father is stated as Harry Hassel, Surgeon. Perhaps the Royal College of Surgeons
can help and also a similar organisation in Germany, say Heidelberg. Not sure if Harry is a German name though? Just a thought.
Also do you have any info on the enrolment details for his two sons who served in the 1stWW. There may be some useful info there.
Jill