Mr. Topsy-Turvy - The Round Way Wrong is the eighth book in the Mr. Men New Library series.
Mr. Topsy-Turvy wishes to buy a new house, or as he puts it "new house a buy". The house he lives in is so topsy turvy, his living room is upstairs, and his bedroom is downstairs. He goes to look for a new house with the estate agent Mr. Homes. Eventually he finds a new house, but the funny part is that it's his own house he wishes to buy despite him already living there.