Hi Justin,
I can't help but wonder if any other members of the family also immigrated to the UK. Other family members who I contacted a number of years ago believe Sunderland is not the original surname, and they thought maybe it was originally Sonderland. I suspect it was neither and is something else - not yet known.
I found the following information on the
http://poznan.jewish.org.pl website for Margonin. I used Google translator to translate from Polish to English.
In 1788, lived in Margonin 232 Jews in 1834, the 483rd Among them were family, Abraham, Baruch Cohen, Diamant, Levi, Manasseh, Schocken, Simon and Spiro.
Since the mid-nineteenth century, the drop of the Jewish population. In 1910 in Margonin lives only 42 Jews. In 1920, 16 Jewish families choose German citizenship and leave the Margonin. Are only two families Lewin and Baruch, at the end of 1935, Abraham will leave Margonin. The last burial in the cemetery took place 6 February 1935 and was buried 55 years old when Bertha Baruch.
Regards
Thorby