The listed coordinates are for what is commonly known as Roundabout Island, you do not have to and do not need to go on the island!
History
Old Turn Junction, or Deep Cutting Junction is a junction between two canals where the Birmingham and Fazeley Canal meets the Birmingham Canal Navigations Main Line Canal. The junction features a circular island.
The circular island is known as Roundabout island and was installed during World War II, to allow the use of temporary dams to protect the railway tunnel beneath it, should the canal be breached by bombing.
The north tunnel of the Stour Valley railway line (main western approach to New Street Station) runs a few yards northeast of the junction, under the Birmingham and Fazeley Canal.
The Cache
At the listed coordinates you will see a finger post on the island, this can be viewed from a number of places, you do not need to visit the island!
The number of letters of the alphabet not used anywhere on the signpost = A
The total number of locks for the three destinations - the total mileage to the three destinations = BC (Disregard the 1/2)
At stage 2 (N 52° 28.777 W 1° 54.827) you will find a BCN post.
The distance to Broad Street - distance to Cambrian Wharf = DE
At stage 3 (N 52° 28.728 W 1° 54.890) you will find another BCN post.
Distance to St. Vincent's Street - distance to Gas street = FG
At stage 4 (N 52° 28.722' W 1° 54.723) you will be standing outside The Brewmaster's House.
It was erected c.180H
There is a seat nearby where you can rest a moment to work out the final coordinates.
Checksum of numbers collected = 32
N 52° 28. (H+F) (B-A) (D+C)
W 1° 54. (G+F) (F-C) (E-C)