To solve this one, you need to work out how the images below are connected as well as answer what would come next in the sequence.
Once you have worked out the connection, you should have two words for each of the buildings, a number associated with each one and the Christian name which links them all. I hope this one isn't too tricky though you may need to get your calculator out for the sums ......
Allocate the following letters :
E=the number of letters in the name of (what was) building A (two words).
F=the number of letters in the name of building B (two words).
G=the number of letters in the name of building C (two words).
H=the number of letters in the name of building D (two words).
J=the number of letters in the Christian name which connects them all (one word).
K=the single digit number associated with A and J.
L=the single digit number associated with B and J.
M=the single digit number associated with C and J.
N=the single digit number associated with D and J.
and finally you need to complete the sequence with :
P=the number of letters in the next building in the sequence (two words).
Q=the single digit number associated with building P and with J.
The cache can be found at : N54 55.Y W001 26.Z
Where Y = ((E + F) x (G + H + M + N - K - L - J)) + P + Q