I would not travel to an area without confirmation of a booking unless I had other business and made contact with other SPs so a plan b was in place.
I would call or at least ring and hang up after 3+rings so whomever is manning the phone knows an enquiry was attempted and can see my unreplied to messages. This is usually enough to get things back on track.
Croydon is plenty busy in the High St area and around the stations. It's actually good that it is quiet and safe to walk some of the interconnecting streets near these busy places. The hazard is perhaps the residential areas prowled by troublemakers and perhaps avoid the busses when the teens are swarming. It's no worse than the likes of Tooting, Clapham, Stockwell, Brixton, Camberwell, Elephant, New Cross, ,catford, Bromley, Lewisham, Sidcup, Wimbledon, New Malden, Kingston, Hammersmith, Ealing, Shepherd's Bush, Stratford and a bunch of other punting locales.