The 1852 census for the Kingdom of Hannover has been filmed, at least in part, and the films are available from the Family History Library. You have to look them up under the appropriate locale (Amtsgericht), then record type Census or perhaps Court Records. So, for example, for Dannenberg, do a place search for Dannenberg, and then Census, then select the item Gerichtsakten 1833-1869.
I haven't done a survey of what precisely is available, but I have used the Hannover census for some locales for the years 1833, 1836, 1842, 1845, 1848, 1852, 1858, 1861, 1864, and 1869 using microfilms at my local Family History Center.
=Jim Eggert