To find the cache you need to visit the co-ordinates and look at the Garage to find the clues.
Stage 1
The coordinates are
N 51 34.ABC
W 001 12.DEF
A - 1st number on the alarm
B - Number of red letters in the name plus 1
C - Number of white triangles on the blue sign
D - Third number in the telephone number (inc dialling code)
E - The number of E's in the red name
F - The second number of the telephone number (exclude dialling code)
Stage 2
The coordinates are
N 51 34.ABC
W 001 12.DEF
A B- The date for Irmgara Powell + 3
C - Number letters in the first word of the wooden sign by gate.
D - Number of white triangles on the blue sign
EF - Lionel Slades Age - 6