There is a footpath down to Station Road from the south side exit. Exit the gateline, keep the station buildings to your right until you reach the end of the station buildings, then turn left down the slope to Station Road. All that's required here is a dedicated marked walkway and better signage. Even today it's a safer walk than crossing the road across the current car park entrance. No need to take the subway to the north side.
An image of said footpath, cropped from Street View. To the left of the white building coming down from the south side of the station:
