Ward office - check up on address

Does anyone know if the ward office will check with a landlord whether I really stay at the address I tell them, or don't they have information about who owns the place I plan to live in?

I do not think that the ward office will look at your address, look into who the landlord is, and check up on you. But note that if you are supposed to be living there, they will send any notification, tax invoices, pension invoices, for example, and if they get the correspondence returned, they will get suspicious.
Also sometimes police randomly come visit new residents in rental properties (just a regular local community patrol) as well. What are you trying to do?