Hi,
Here they are in 1891, same address as 1901

1891 RG12/803 f.40 p.31 Brighton
15 Crescent Cottages
PITT
Henry Head 49 Painter London
Fanny Wife 40 Brighton
William Son 14 Page
Charles Son 13 Scholar
Samuel Son 12 " "
Joseph Son 11 " "
Louisa Daur 9 " "
Anne Daur 7
Leo Son 3 All children dittoed as born Brighton
I also found this on the IGI,
Samuel PITT
Birth: 16 MAR 1878 Dublin, Ireland
Father: Henry PITT
Mother: Fanny Mosely PITT
Looking at the different birthplaces of the oldest children I wonder if Henry was in the army before settling in Brighton

Do you have their marriage cert. ?
Henry PITT Mar Q 1873 Brighton 2b 258
Fanny Mosely with same details.
which might confirm this and/or help find Henry in earlier censuses.
Regards
Daisy