The cache is not at the posted coordinates, but can be found at:
N 51° 1X W 000° 3Y
To help with the first step of the puzzle, there are a complete set of 'alternatives' in the Image Gallery.
In step 2, you will find ambiguities. A lot of ambiguities. (Yet it all seemed so clear when I was setting this up!) I haven't gone out of my way to be obscure so, if in doubt, pick the obvious one - he is the star after all!
For assistance with disambiguation, click here.
And finally, the checksum for A to H is 602 - although only seven really contribute to this total...
The cache is close to a busy road, so please be careful.
Congratulations on the FTF to clarkester.