Don't call me Shirley Mystery Cache

This puzzle is my tribute to a comic actor who passed away last week - one that ranks with the best. It shouldn't take you too long to work out his identity (the title will help), but that's the easy part ... can you find the coordinates of the cache?

The cache is not at the posted coordinates, but can be found at:
N 51° 1X W 000° 3Y
where 1000*X=(D*F)+(A+C+12)
and 1000*Y=(G*H)-(B+E+28)

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.