They're in Ballards Lane, Finchley in 1891 (Fritz and Fanny* Haedicke, both born Germany, with "son" William, 3, b Finchley). Also in the household are a Felix Merseburg, brother in law, and one servant: RG12/1057/13/18.
* I see that she is certainly Jenny in 1901 and at death in 1926, so the 1891 is possibly an enumerator's error, mistranscribing from the household schedule.