From The Anvil Heavy duty tubular bathroom deadbolt in 4 sizes

Heavy duty tubular bathroom deadbolt in 4 sizes

From the Anvil deadbolt for use with bathroom thumb turn in SSS Satin Stainless Steel

Sizes and dimensions.

91103 (was 18364) 2.5 inch 64mm, Backset 44mm
91100 (was 18361) 3 inch 75mm, Backset 56mm
91101 (was 18362) 4 inch 100mm, Backset 81mm
91102 (was 18363) 5 inch 127mm, Backset 106mm

Backset length is measured from the edge of door to centre of the spindle

These deadbolts take a 5mm spindle
Rebate Kit 91106 (was 18369) sold separately.

This unit a a good match for the 18336 bathroom thumb turn