The Pestilence that Walketh in the Darkness Mystery Cache

EF Benson is best known for his Mapp and Lucia tales, but he was a prolific writer and wrote many ghost stories as well. So snuggle up with your favourite beverage and indulge yourself for a while.

There is nothing to help you at the posted coordinates, although it has a passing significance.

Find the correct story and once you have read it answer the following questions.

1. How many miles to Polearn? = A

2. How many  miles further to travel to the market at Penzance? = B

3. I came to Polearn first at what age? ='1C

4. How many hours out of 24 did I scarcely pass behind windows and wall? = D

5. Which panel concerned me most of all? = E

6. Pestilence that walketh in the darkness is from which psalm? = 9F

7. How many years ago did Mr Dooliss half build the house again? = G

8. After 20 years I was earning a yearly income of how many figures? = H

9. How many years ago must it have been since Mr Dooliss died? = J

10. Which month was it when the sunset still burned in the sky? = K

The cache can be found by working out this little equation 

N51 H G. C (A+B) (E+G)  W008 2 (H+D). (K-F-F) (J-A) B

You can validate your puzzle solution with certitude.