I recently saw SASP-15KA in the ACDC catalogue and for R140 it's cheap insurance.
https://a365.acdc.co.za/Images/spec/...0SASP-15kA.pdf

I see it has a rating of 15kA and 275V and uses MOV's (which arrest surges by simply shorting the supply once the voltage goes above the threshold)

It doesn't say how it should be installed though.
Does SANS specify where it should be installed?
I would imagine it should be installed after the mains isolator. So the neutral output of the mains isolator connects to the bottom of SASP-15KA, and the live output of the mains isolator connects to the top of SASP-15KA ?