To get to this cache, park at the bottom of the hill and walk up, then afterwards, purchase a certificate from the shop at the bottom of the hill.
This cache is a replacement for Matchbox Memories which was rather hammered by muggles during it's last few months.
As this is a popular and well-populated area a reasonable degree of stealth is required.
*curse you Wales for taking the title of World's steepest street off this! (July 2019)