Preston Lighthouse. Multi-Cache

I driven passed this many times and it's only just dawned on me, that, er Preston is some way from the sea.

There is little to no info about the lighthouse on the t'internet and no info on site, very odd, must be top secret.

The Lighthouse.

Navigate to the published co-ordinates and find the numbers to reveal the cache co-ords:

Assume: N 53° 45.AC(B*2) W002° 44.B(B*2)(C-7)

A = The number of words on the sign beneath Firemans switch on the right side of the lighthouse.

B = The number of panes of glass in ONE of the Lighthouse windows between the upper and lower lighthouse walkways ( They're all the same ).

C = The number of windows in the Lighthouse between the upper and lower lighthouse walkways.

Checksum: The last six digits of the Northing and Westings should add up to 33.