Possibly a generation or four, as per my east end immigrant ancestory. German arrival circa 1830, gradually drifting east through Whitechapel, Beffn'll Green, Limehouse, West Ham, Silvertown then hopped over the river to Woolwich before dad was born in '39.
As for integration - he married a girl from Aldgate and tuned pianos but his descendants were in coopering, possibly linked to the germanoid sugar industry in the east end, and they married non-teutons.
Jews of East End? Probably in and out within 60-70 years?
It was between a hundred and two hundred years for the Hugenots of Soho to be fully integrated, according to the book I just read. And in those days there were no political forces encouraging people not to integrate, despite prejudice being far stronger in the past than today.