I now see that Northolt in in London and there are many with the Carr surname in London. First names include Philip, Elizabeth, Edwin, Charlotte, Lillian, Nellie, Beatrice, Ernest, Grace, William, Robert and so on. These are all in the 1911 England and Wales Census.
Is that the time frame you are looking at? There are over 40 pages of people with the Carr surname. Can you narrow down the range of years or call out specific first names?