The part number for an extra contact , N/O , to go into 56PBS1 is -
ZENL1111
Please go to the following links below and check under the Documentation Tab for more information.
Australia - https://www.se.com/au/en/product/ZENL1111/harmony-xald%2C-xalk%2C-single-contact-block%2C-screw-clamp-terminal%2C-1-no/
New Zealand - https://www.se.com/nz/en/product/ZENL1111/harmony-xald%2C-xalk%2C-single-contact-block%2C-screw-clamp-terminal%2C-1-no/