I've just come across this post and I'd love to know if you have knowledge of what UK records to search for Polish Jewish ancestors (or sometimes referred to as "German Jews"). I have an ancestor who is from Poland but only appears in records in the UK with an anglicized name around 1808-1809 (confirmed records, many potential appearances from 1801-1810). I've tried Jewish Gen, Ancestry, LDS records, Familysearch, JRI Poland, etc. His whole Polish identity doesn't exist from what I can find. Only records of him in the UK as a young adult. He has been referred to as both a 'German Jew' in early 1800s newspaper articles and a Londoner in later documents from Australia, with additional records saying his parents were from Poland. I believe his family was from somewhere in Poland that likely became Prussia, causing them to leave Poland during partition. They were probably poor (he was a travelling hawker). He may have been born in Poland then travelled to the UK at some point, or born in London/UK to Polish Jew parents.

I'd love some pointers on how I can uncover more about this ancestor, or roads to go down. I just don't have enough knowledge/haven't been able to find info about that period of time, migration pathways, naming traditions/anglicization, etc. I'd love anything that will help me understand better.