The Life Blood of London Mystery Cache

Small box. No magnet so be careful!

There is no need to go to the coordinates shown but the actual location of the cache is within walking distance from the shown coordinates.

puzzle can be worked out at home and the only excursion you need to make is to retrieve the cache!

Congratz to groosome for FTF!

Puzzle: 

coordinates are: 

N A B.CD

W E F.GH

A) -1

B) -20

C) is the number

D) +3

E) -9 

F) /7 (divide by)

G) is the number

H) +1

A and H are the same number

C,E and G are also the same number

B,D,F and H are 2 digit numbers.

have fun!

You can check your answers for this puzzle on GeoChecker.com.