In my job I visit loads of nurseries and early years settings, so I feel I can report! Names seem mainly area dependent but popular ones are
Boys:
Leo, Theo, Albie, Arthur, Noah, Harry, Roman, Carson, Hunter, Freddie, Luca, Arlo, James, Teddy
Girls:
Florence, Isabella, Maeve, Iris, Ivy, Sylvie, Sophie/Sophia, Mia, Penelope, Harriet, Mya/Maya, Freya, Harper, Isla, Ada