'C' is for Caterham.
Caterham (/ˈkeɪtᵊrəm/) is a town in the Tandridge District of Surrey, England. The town is administratively divided into two: Caterham on the Hill and Caterham Valley that includes the main town centre in the middle of a dry valley but rises to equal heights to the south. The town lies close to the A22, centred 21 miles (34 km) from Guildford and 6 miles (9.7 km) south of Croydon, in an upper valley cleft into the dip slope of the North Downs. Caterham on the Hill is above the valley to the west. Due to its proximity to London, Caterham is a commuter town. The North Downs Way, a popular National trail with walkers passes very close to the town.
This is a simple offset puzzle that hopefully everyone can solve, then with a simple field puzzle element which may or may not be easier.
The final is one of those where if you do not sign my log placed in the cache you cannot claim the find. You'll understand when you get there.
Very close to the posted coordinates look around. What year did this bird start scouting out for nests? =ABCD
Now assuming N 51 and W 000 you will find the final coordinates for the Northings minutes are at ABCD divided by 122.251 to 3 decimal places. The West minutes coordinates are at ABCD divided by 403.641 to 3 decimal places.
This cache was placed by MuzzaDazzler
Bonus Cache
Bonus numbers will be present in some of the caches in the series, collect these numbers as you will need to use them should you wish to find the series bonus '* - Bonus Cache - Surrey A-Z'