GEOCACHING ON NATIONAL TRUST PROPERTY IS AT YOUR OWN RISK.
Also, please note that the National Trust is caring for the specialist habitats and landscape you enjoy on this and other caches on NT property, which is one of the reasons we are glad to be members.
Stage 4 - a puzzle where you don't need Google
You could use Google for some of these, but frankly you don't need it, and it's a lot more fun if you work it out yourselves. If you get stuck ask the kids for help.
A B = Mother's local
C = Library conversation
D D = Istanbul harem
E = Whisky jokers
F = Elizabethan pluckers
G H = 9,10,11 etc.
J J = Home-built pet
K L = Saville Row
Where GH is plural (I know that's not quite right, but it's easier than rejigging the whole puzzle!), and check your spelling - one isn't spelt the way you think.
N51 C+E.(D+1)(L-A)G W000 (F+K+1).(B+H)(A+J)(F-D)
Here is a link to the hints pages, which will help you to solve the puzzle, and which you can click on if you get stuck.