Welcome to the new forum. We're now hosted on ElectriciansForums.net rather than ElectriciansForums.co.uk - Chat about the forum upgrade by CLICKING HERE
Discuss Testing RCBO at Light Switch in the Electricians Forum Rules area at ElectriciansForums.net
That is a lot of faff when , As has been stated, you are testing the circuit to the accessory to check the functionality of the RCD part of the RCBO. Now a ramp test is different and would warrant disconnection.Also I think some rcds / rcbos actually need short pieces of cable on the load side to get a reading.
Here's one of them aforementioned debates;
RCD Test on lighting circuit protected by RCBOs - https://www.electriciansforums.co.uk/threads/rcd-test-on-lighting-circuit-protected-by-rcbos.114565/