A multi cache starting on the Thames Path near a reserve for the Two-Lipped Door Snail.

The Thames is very close here. Be alert if caching with children! 

Maximum stealth required. The tow path can be very busy.

The posted coordinates take you close to the junction of the Thames Path and the path to the National Archives. You are looking for a sign about the Two-Lipped Door Snail that you are able to read. Study it closely for the following information. Can't read the sign??? Maybe you need to be closer to the coords or look around a bit more????????
 

A = According to the map legend, how many recent distribution records are there for the Two-Lipped Door Snail? Double this answer. 

B = How many letters are there in the second word of the Two-Lipped Door Snail's scientific name? 

C = Total number of Two-Lipped Door Snails drawn on the entire sign?

D = How many letters in the missing word of the book A Field Guide to the ??? Snails of Britain and N.W. Europe?

The cache is at N51 28.ABB W000 16.CDC

The cache is not on private property. If your coordinates lead you somewhere like that, best you check again.

Bring Your Own Pen and watch out for dog pooh! 

** thanks to the unknown snail illustrator. All credit to you.