w124804975 is clearly a footpath, physically and legally. w398198578 is less clear, especially since it was just resurfaced and now shares the asphalt with w124804969, only a white line separates them now.

I can't see any NCN signs at all, there is a Red Squirrel Trail sign at the bottom of these steps pointing west. I would assume by the road.

There is also another Red Squirrel Trail sign pointing south in the same place, then via Marine Cross Road and north on Regent Street.

So when travelling west to east it's clear. Via Marine Cross Road.

Travelling east to west is not clear, it's either via Carter Road or via these steps. I've seen plenty of people going up and down these steps, it also has a bike gutter ramp on both sides.