I looked up the refs from Brian Lawson's census index for 1891, and Ancestry has mixed up two households - they are in the index under Clarke. Their household follows the Clark youngest son Robert aged 5.
The Callister entry (as you have it) is at 3 Beach Street, Schedule no.135.
Christian Callister, "Armanda" and Christian A.

You can find them under Armanda Clarke or put in Piece 4683 Folio 44.

Sue