The replacement for a Merlin Gerin 26860, RCBO, 240V, 20A, 30mA is a A9D11820.
See link for further details:https://www.se.com/au/en/product/A9D11820/ic60h---earth-leakage-circuit-breaker---1p-%2B-n---c-curve---20-a---30-ma---240-v/
See link for further details:https://www.se.com/au/en/product/A9D11820/ic60h---earth-leakage-circuit-breaker---1p-%2B-n---c-curve---20-a---30-ma---240-v/