Minimum thickness self levelling concrete to level exterior step

[Kerlaan]

Hello all

I have an exterior concrete poured step that is not level. I think that the "cream" after pouring found a way through the foundation. It varies from about 2mm (1/16 inch) through to about 19mm (3/4 inch) on one corner, at the rising face.

The step (or landing zone is a better phrase perhaps) is 120cm by 100cm at the top of a flight of 2 steps from a gravel path onto a patio edge.

Does anyone have a recommendation for correcting this please. I was thinking of a self levelling concrete but concerned about minimum thickness.

Thanks in advance