The listed coordinates take you to a Victorian postbox set into the wall.
To find the final container note down the following info from the white sign on the box
Monday to Friday Collection Time - A.00 am
Saturday Collection Time - B.00 am
Later Collection Time at Breage - C.00 pm
Latest Collection Time in the area - D.30 pm from Helston Post Office
Post Box number TR1E FG Checksum of A - G is 31
The final is at N50 04.A (B+F) (C+D) W5 19.G (C+E) B
The final location is a short walk away and can be very busy - Please be aware of muggles and hide the container out of sight..