tracing ancestry

hi everyone! (please tell me if this should be posted elsewhere)

i recently found out that great-grandmother was jewish, so i began to trace that side of my ancestry. however, i’ve only managed to get back to 1700 and can’t find any further records of the family. i’d like to learn more about where our family emigrated from but they have lived in the united kingdom for nearly 400 years. i’m not very knowledgable of the religion or ethnicity, so please feel free to tell me some useful information- i am willing to learn about this side of my heritage.

is there a way of tracking records further or have i hit a dead end? i’ve tried ancestry but they have no birth records last 1700 for my family.

thank you!