It's not a numeric sum. The only reason i got the location was because i spotted the pyrmaid and wikipedia'd the location where some of the clue appeared. part of it is rather cryptic!
You'll know when you've found the j-50-9, but as for the I.L.P....
Just had another guess today, which was wrong.
On a side note, the same shop have on display an Isis which is Red and Gold. Does anyone know whether this is a 'special' Isis, or is it just a display one (it has a little dent on it, so I wonder whether it is just being used for display purposes).
First line gives you the location. I wondered wether j59 was perhaps an area at the location, but just asked staff and was pointed in the right direction.