IceColdUK: After 15 years, time for this puzzle to go.
For those interested, the puzzle was based on The Great Bear, a 1992 lithograph by Simon Patterson. The work resembles the London Underground Tube map, but Patterson uses each line to represent notable but seemingly random people (and planets) grouped into categories corresponding to each Tube line.
https://www.tate.org.uk/art/artworks/patterson-the-great-bear-p77880
For the Northings, the puzzle identified people on the "Film actors" (or Northern) line; for the Westings, people on the "Louis" (or Central) line. The required values came from the grid references on the map.