It will be a mess to diagnose if there’s anything wrong with the electrical not to mention fire risk as the cable sizing will be different between light and sockets. The weak link will burn up in a short circuit and may not even trigger MCB to trip. Hence better not.

The neutral existence for lights, starts at the light point itself on the ceiling and back to DB.

Final circuit not supposed to be joined so to be code compliant by right have to pull all the way from DB to wherever the switch is.
Alternatively you can tap on the 13A SSO point "like looping socket" but have to upgrade all the wiring to 2.5mm to match the SSO MCB and existing SSO cable size.

In the correct flow the Live still fed from the light circuit and smaller MCB,
in the reversed flow "should anything go wrong on the socket neutral" - the socket MCB is 20A or higher because its cables are all 2.5mm or higher, light circuitry Live at 1.5mm will burn before the 20A MCB trip.

This is why it is not recommended to mix and match. It is a safety risk.

However if you mount the switch at the light point itself then you already have a L and N.

This post has been edited by ceo684: Mar 30 2023, 10:21 PM