I drove north up the A22 (Godstone Road), I then turning a hard right I drove up Downscourt Road.
I can see from the Croydon web page that purley is one big Permit Zone, but I have retraced my route to the point I entered the parking zone and a few hundres yards past this point and there are NO signs.
I was visiting a friend who lives there, and she confirmed that they do not need permits, she has lived there for the past 3 years.