FLAMME/FLEMME from Saltzgitter in Hannover?

Hello Listers,

I have found reference to what may be a connection to my English born
grandmother Edith Sophia FLEMME, born 1884, the daughter of Hermann Flemme
born 1831, the son of Heinrich Flemme, Hannover.

Entries in the Hull German Church Register record:

Sophie EHLERS baptized 20/3/1884, Grandparent to Edith Sophie FLAMME.

Sophie Christiane Hedwig Ehlers, Mrs Franz Henning Jacob FLAMME.

My great grandfather Hermann FlEMME lived with this family:-

Charlotte BIELSTEIN baptized 29/10/1845 in SALTZGITTER, Hannover
widow of musician Conrad EHLERS born about 1830-1831 Hannover

We think this is Charlotte's family:-
musician August BIELSTEIN born 10/3/1839 in Merlau, Darmstadt
married to Anna Maria GRIN (GREIN?)

Wilhelmine Melosine GUNTHER b 13/7/1813 in SALTZGITTER, Hannover

Captain Hermann DETTMAN (fischer) and his wife Sophie.

Could somebody tell me which parish records I should look in and where are
they kept?

Thank you